A student understands a scientific process but cannot explain it in the language of the examination.
Another student knows the correct mathematical method but struggles to describe the reasoning behind it.
A third student can discuss a historical event intelligently in conversation but produces a weak written answer.
All three may receive disappointing examination results.
But what, exactly, has been measured?
Their knowledge?
Their language proficiency?
Their ability to organise ideas?
Their familiarity with examination conventions?
Or some combination of all four?
The distinction is not merely philosophical. It determines what teachers should teach, what examiners should assess, and what students need to improve.
A student can know something without being able to demonstrate it in the form an examination requires. But that does not automatically mean the examination is measuring the wrong thing.
The real question is whether the required form of demonstration belongs to the competence being assessed.
1. Knowledge and Expression Are Related, but They Are Not Identical
Imagine asking a student to explain why ice floats on water.
The student may understand that ice is less dense than liquid water.
They may have observed the phenomenon, discussed it during lessons, and correctly predicted what would happen in a practical experiment.
Yet their written explanation might be:
“Because ice is lighter.”
This statement is incomplete and potentially misleading.
A small piece of ice is not necessarily lighter than every quantity of water. What matters is density, not total mass.
Does the answer prove that the student does not understand density?
Not necessarily.
But neither does the student’s supposed understanding prove that the answer is sufficient.
There are at least two possibilities.
The student understands the relevant relationship but cannot express it precisely.
Or the student has only an approximate understanding and does not recognise why the distinction matters.
An examiner who sees only the written answer may not be able to determine which explanation is correct.
That is a limitation of the evidence available, not necessarily a failure of professional judgement.
It also explains why examiners cannot award marks for meaning that has not been demonstrated.
The challenge for education is to develop assessments that reveal understanding without introducing unnecessary barriers to demonstrating it.
2. What Is the Examination Supposed to Measure?
Before evaluating an answer, we need to identify the intended competence.
In educational assessment, this is often called the construct: the knowledge, skill, or ability that the assessment is designed to measure.
Consider three tasks.
Task A: Calculate the density of an object using its mass and volume.
Task B: Explain in English why density determines whether an object floats.
Task C: Explain the same relationship using accurate scientific terminology in German.
These tasks overlap.
But they do not assess exactly the same thing.
Task A primarily concerns mathematical and scientific calculation.
Task B adds the ability to construct a scientific explanation in English.
Task C also requires competence in German scientific language.
If the examination is designed to assess scientific communication in German, the language requirement is not an accidental obstacle. It is part of the objective.
If the examination is intended to assess only the student’s ability to calculate density, an extensive written-language requirement may introduce an additional difficulty that is not central to the task.
This distinction matters because assessment results are meaningful only when we understand what contributed to them.
A low score may indicate weak subject knowledge.
It may indicate insufficient language proficiency.
It may indicate difficulty connecting knowledge to a particular form of explanation.
And sometimes the available evidence does not allow us to separate those possibilities confidently.
3. Mathematics: Does the Student Need to Explain Every Step?
Consider a student solving:
3x + 7 = 22
The student writes:
x = 5
The answer is correct.
But suppose the examination asks:
Solve the equation and show your working.
The student has demonstrated the result but not the method.
That difference matters.
The examiner may need to determine whether the student understands the operations or has simply guessed the correct value.
A second student writes:
3x = 22 − 7
3x = 15
x = 5
The second response provides visible evidence of the procedure.
Now consider a third student who solves the equation mentally and can explain the method orally but cannot easily organise the steps in writing.
The student may possess the mathematical competence being assessed.
However, the submitted answer does not provide all the required evidence.
This creates a legitimate educational problem: how can the student learn to make their reasoning visible?
The answer is not necessarily more mathematics.
It may be practice in mathematical representation.
Mathematical communication is not merely decoration
Symbols, diagrams, equations, and written explanations are tools for making mathematical reasoning inspectable.
A student who understands a problem intuitively may still need to learn how to present a solution that another person can verify.
At the same time, an assessment should not require elaborate prose when a concise mathematical demonstration would be sufficient.
The appropriate form depends on the objective.
If the purpose is to assess algebraic manipulation, symbolic working may be enough.
If the purpose is to assess mathematical argumentation, explaining why a procedure is valid may be essential.
These are different skills.
A well-designed examination should distinguish them.
4. Science: Knowing the Mechanism Is Not the Same as Naming It
Scientific education introduces another difficulty.
Students may understand a phenomenon through observation and practical experience before they can describe it using precise terminology.
Consider evaporation.
A student may correctly observe that a wet surface dries faster in warm, moving air.
They may understand that temperature and airflow influence the process.
But when asked to explain the phenomenon, they might write:
“The water disappears faster because the air moves.”
This is not a complete scientific explanation.
The water does not simply disappear. Molecules escape from the liquid into the surrounding air, and airflow can help remove water vapour near the surface.
The student’s response identifies a relevant factor but does not explain the mechanism adequately.
Would a diagram help?
Possibly.
Would an oral explanation reveal additional understanding?
Possibly.
Would the student still need to learn scientific terminology?
Certainly, if accurate scientific communication is an educational objective.
The point is not to excuse incomplete explanations.
It is to recognise that scientific competence can have several dimensions: observation, prediction, conceptual understanding, procedural knowledge, and communication.
A single written answer may provide evidence of some dimensions more clearly than others.
Why this matters in biology and chemistry
In biology, students must distinguish processes that appear similar but operate differently.
In chemistry, a student may understand that a reaction produces a gas but struggle to construct a balanced chemical equation.
In physics, a student may predict motion correctly but confuse force, energy, and momentum in their explanation.
These differences matter because scientific language does not merely label ideas.
It helps define relationships between them.
An imprecise term can conceal a correct intuition.
It can also expose a genuine conceptual misunderstanding.
Teachers need to determine which is happening before choosing the next instructional step.
5. History: A Student Can Know the Facts but Fail to Build an Argument
Historical knowledge is often evaluated through written explanation.
But knowing historical facts and constructing a historical argument are not identical skills.
Imagine two students studying the causes of the First World War.
Both know about alliances, militarism, nationalism, and the July Crisis.
The first student writes a long list of facts.
The second selects relevant evidence and explains how particular developments contributed to escalation.
The second response may receive a higher score.
That does not necessarily mean the second student knows more historical facts.
It may mean the student has demonstrated stronger historical reasoning.
And if the examination is intended to assess historical explanation, that difference is legitimate.
The problem arises when students are not taught the distinction.
They may believe that adding more information automatically produces a better answer.
But an argument requires relationships.
For example:
“The alliance system increased the risk that a conflict involving individual states would draw in additional powers.”
This sentence does more than name the alliance system.
It explains a mechanism.
A student who knows the relevant facts but cannot express their causal relationships needs help with argument construction.
That is not the same as needing to memorise another chapter.
6. The Language Barrier in Academic Subjects
Now consider a student who understands the subject in Ukrainian but must complete an examination in German.
The student may know the concept, recognise the correct procedure, and solve practical problems.
Yet the examination question contains unfamiliar academic language.
In mathematics, the student encounters:
Begründen Sie Ihre Antwort.
The instruction requires the student to justify the answer.
A student who interprets it as simply give the answer may provide a correct result without the requested reasoning.
In biology, the instruction might be:
Erläutern Sie den Zusammenhang zwischen Struktur und Funktion.
The student must explain the relationship between structure and function.
Knowing the vocabulary Struktur and Funktion individually is not sufficient.
The student must understand the academic operation expressed by erläutern and the relationship expressed by Zusammenhang.
A weak answer may therefore reflect a language-processing problem rather than a lack of biological knowledge.
But the distinction is not always easy to establish.
Academic language is not ordinary conversational language
A student may communicate confidently with friends and teachers while struggling with examination instructions.
Conversational fluency does not automatically provide competence in academic explanation.
School subjects introduce specialised verbs, nominal constructions, logical connectors, and conventions for presenting evidence.
This is why studying an academic subject through another language requires attention to both dimensions.
The student must learn the subject.
The student must also learn how the subject is communicated in that educational system.
In German language learning, this means that everyday communication and academic proficiency may require different kinds of practice.
Neither should be mistaken for the other.
7. When Language Errors Matter — and When They Should Matter Less
Consider a biology examination written in English.
A student writes:
“Water go from roots to leaves through xylem.”
The sentence contains a grammatical error.
But it communicates a relevant scientific fact: water moves from roots toward leaves through xylem tissue.
Should the student lose marks?
The answer depends on the assessment objective and the applicable marking criteria.
If the examination assesses biological knowledge and the scientific meaning is sufficiently clear, grammatical accuracy may not be an independent scoring requirement.
If the task explicitly assesses academic English, language accuracy may be relevant.
If the grammatical error changes the scientific meaning, it may also affect the subject score.
These are not interchangeable situations.
A fair assessment should avoid penalising the same language error in ways that are unrelated to the stated objective.
But it should also recognise that some linguistic distinctions are scientifically essential.
Compare:
“All bacteria cause disease.”
“Some bacteria cause disease.”
The difference between all and some is not a minor stylistic issue.
It changes the biological claim.
Similarly:
“Temperature increases because pressure decreases.”
“Pressure decreases because temperature increases.”
The same words appear in both sentences, but the proposed causal relationship is reversed.
The scientific validity of either statement depends on the physical system and conditions.
Language is therefore not always a separate layer placed on top of knowledge.
Sometimes it is the means by which the knowledge is specified.
8. The Danger of Mistaking Fluency for Understanding
There is another side to the problem.
A student may produce a polished answer without understanding the subject deeply.
They may memorise a definition, reproduce a textbook explanation, or use sophisticated vocabulary.
The answer sounds convincing.
But can the student apply the idea to a new situation?
Consider the statement:
“An increase in temperature causes an increase in the average kinetic energy of particles.”
A student may reproduce this sentence accurately.
But suppose the teacher asks:
Why does a thermometer not measure the total thermal energy of an object?
The student must distinguish temperature from the total energy associated with a system.
Repeating the memorised sentence may not be enough.
This is why linguistic fluency can sometimes create an illusion of understanding.
A well-expressed answer is not automatically a well-understood answer.
And a poorly expressed answer is not automatically evidence of weak understanding.
Assessment must look for the relevant reasoning.
The challenge is to design tasks that reveal it.
9. Why Oral and Written Performance Can Differ
Some students explain complex ideas effectively in conversation but struggle with written examinations.
Others produce excellent written work but find spontaneous oral explanations difficult.
These differences can arise from several factors.
Spoken communication allows immediate adjustment.
A listener can ask for clarification.
A speaker can reformulate an idea.
Gestures, intonation, and shared context can support meaning.
Written examination answers often lack those opportunities.
The student must anticipate what the reader needs.
The structure must be clear without further explanation.
Relevant assumptions may need to be stated explicitly.
This does not make written assessment inherently unfair.
Writing is itself an important academic skill.
But the assessment designer should decide whether written expression is part of the intended competence or simply the chosen method of collecting evidence.
For example, a written essay is appropriate when the objective is to assess academic writing and argumentation.
It may be less direct when the objective is to assess a practical skill that could be demonstrated more accurately through performance.
The method of assessment should follow the educational purpose.
10. What Happens When Students Learn a Subject in Two Languages?
Bilingual and multilingual education introduces another important question.
Can a student understand a concept in one language but struggle to retrieve or explain it in another?
Yes.
A student may learn the concept of density in Ukrainian, later encounter Dichte in German, and then be asked to explain it in English.
The scientific relationship remains the same.
But the linguistic routes used to access and express that relationship differ.
The student may recognise all three terms without being equally comfortable using them in an explanation.
This distinction between recognition and active retrieval matters.
Recognising a word on a page is not the same as producing it accurately under examination conditions.
Nor is retrieving a term equivalent to understanding the underlying mechanism.
A student may need to develop all three abilities:
recognising the concept, retrieving the relevant terminology, and applying the concept in context.
The danger of translating without understanding
Suppose a student memorises:
Dichte = density.
That is useful vocabulary knowledge.
But it does not establish that the student understands density as mass per unit volume.
Likewise, memorising a formula does not guarantee the ability to identify when it applies.
Effective subject learning through another language should connect the term, the concept, the procedure, and the real-world situation.
This approach is relevant to international education, including students moving between educational systems or preparing to study academic subjects abroad.
11. Can an Examination Separate Knowledge from Language Completely?
Not always.
Almost every examination requires some form of communication.
Even a mathematical equation uses a symbolic language.
A diagram depends on conventions.
A practical demonstration must be interpreted.
A multiple-choice answer requires the student to understand the question and distinguish the options.
The goal should therefore not be to imagine an assessment entirely free from communication.
The more realistic goal is to reduce barriers that are irrelevant to the competence being measured.
In assessment theory, this problem is often described in terms of construct-irrelevant variance: differences in scores caused by factors that are not intended to be part of the measured ability.
For example, unusually complicated wording may disadvantage students in a mathematics examination when that complexity is unnecessary for the mathematical task.
But the same wording may be entirely appropriate in an examination specifically designed to assess academic reading.
Context determines whether the language demand is relevant.
There is no universal rule that simpler wording always makes an examination better.
A medical student, for example, may need to understand complex professional terminology because that terminology is part of competent medical practice.
The central question remains:
Is this difficulty part of the skill we intend to assess, or is it an unintended obstacle to demonstrating that skill?
12. How Teachers Can Diagnose the Real Problem
When a student gives a weak written answer, the next step should not automatically be more memorisation.
A useful diagnostic approach is to compare different forms of evidence.
Ask the student to explain the idea orally.
Ask for a diagram.
Present a practical example.
Change the wording of the question without changing the underlying concept.
Ask the student to identify the relevant relationship or procedure.
Then compare the results.
If the student consistently fails across formats, a conceptual gap becomes more likely.
If the student demonstrates understanding through one format but not another, the difficulty may concern representation, language, or task interpretation.
These observations do not provide a perfect diagnosis.
But they are more informative than treating one disappointing answer as a complete description of the student’s ability.
A practical example
A student cannot explain photosynthesis in German.
The teacher asks the student to describe the process in Ukrainian.
The student gives an accurate explanation.
The teacher then provides the essential German terminology and asks the student to reconstruct the explanation.
The student succeeds.
This suggests that the original difficulty was at least partly linguistic.
The appropriate intervention is therefore different from reteaching the entire biological process from the beginning.
The student needs to connect existing subject knowledge with the language required to demonstrate it.
That is a more precise educational response.
13. What Students Can Do Before an Examination
Students cannot always choose the assessment format.
But they can prepare to express knowledge in the form required.
The first step is to identify what the examination actually assesses.
Does it require a final answer?
A calculation with working?
A written explanation?
A comparison?
An argument supported by evidence?
A specific grammatical structure?
A practical demonstration?
The second step is to practise producing the required evidence.
Knowing a concept privately is not the same as demonstrating it under examination conditions.
The third step is to compare performance across formats.
If a student can explain a topic orally but not in writing, writing practice may be necessary.
If the student can solve a problem in Ukrainian but not understand the German instructions, academic-language practice may be necessary.
If the student can repeat a definition but cannot apply it, the conceptual understanding may need further development.
The fourth step is to review mistakes by their actual cause.
Not every wrong answer is a knowledge error.
Not every language error is harmless.
And not every correct answer proves complete understanding.
This distinction helps students prepare more efficiently.
14. What Examiners Can and Cannot Infer
An examiner evaluates the evidence provided within the assessment.
That evidence may be extensive or limited.
A correct answer can support an inference that the student possesses relevant knowledge.
A well-justified answer may provide stronger evidence of reasoning.
An incorrect answer can reveal a misconception.
But one answer rarely establishes everything about a student’s underlying competence.
This matters especially when the task requires several abilities simultaneously.
A weak written response may result from insufficient subject knowledge, language difficulty, time pressure, misunderstanding of the question, or a combination of these factors.
The examiner may not be able to identify the precise cause from the submitted answer alone.
That does not mean the score is meaningless.
It means the interpretation of the score should remain proportionate to the evidence.
A result can validly describe performance on a particular assessment without serving as a complete judgement of the learner’s intelligence, potential, or knowledge in every context.
15. The Difference Between an Exam Result and an Educational Diagnosis
An examination result answers a relatively narrow question:
How did the student perform against the specified criteria under the assessment conditions?
An educational diagnosis asks a broader question:
What does the student understand, what can they do, and what is preventing further progress?
These questions overlap.
But they should not be confused.
A score of 60% may be useful for reporting performance.
It does not automatically tell a teacher which intervention will help.
One student may need stronger conceptual foundations.
Another may need practice interpreting examination instructions.
A third may need academic vocabulary.
A fourth may need help organising explanations.
The same score can arise from different difficulties.
This is one reason why some students know more but score less.
The score describes an outcome.
It does not, by itself, explain the mechanism that produced it.
16. What This Means for International Education
Students who move between countries or educational systems may encounter unfamiliar expectations even when they already know the subject.
A student accustomed to short factual answers may enter a system that expects extended explanations.
Another may be familiar with essay-based assessment but encounter tightly structured tasks with specific marking criteria.
A third may understand mathematics but struggle with the terminology used in a new language of instruction.
These transitions require more than translation.
They require understanding how knowledge is represented, taught, and evaluated in the new educational context.
The international work of Levitin Language School and its US-facing educational branch, Language Learnings, reflects the importance of distinguishing language learning, academic subject support, and learning subjects through another language.
A student preparing for a formal language examination may need focused work on its official requirements.
A student developing subject knowledge may need conceptual instruction.
A student studying mathematics, biology, or history in a foreign language may need an integrated approach.
These objectives are connected.
But treating them as one undifferentiated problem can make education less effective.
17. Three Contexts, Three Different Standards
There is a final distinction worth preserving.
The same response can be evaluated differently depending on the context.
In the learning process
An incomplete answer can be valuable evidence of developing understanding.
The teacher can ask questions, explore the student’s reasoning, and help refine the explanation.
The purpose is development.
In a formal examination
The response must be evaluated according to the applicable criteria.
The examiner cannot automatically award marks for knowledge that was not demonstrated.
The purpose is standardised assessment.
In real life
The decisive issue may be whether the communication enables the required action.
A person may explain a problem imperfectly but successfully obtain help.
A professional may use grammatically simple language while communicating a technically correct decision.
The purpose is practical effectiveness.
These contexts are not interchangeable.
A teaching method that works during exploratory discussion may not prepare a student adequately for a tightly specified examination.
An examination answer that earns full marks may not be the most natural or effective way to communicate in everyday life.
And practical communication that achieves its goal may still contain errors that matter in a formal language assessment.
Understanding these differences allows students and teachers to choose appropriate standards rather than treating one standard as universal.
Conclusion: Knowledge Must Be Demonstrated, but the Demonstration Must Be Relevant
A student who cannot express an answer may possess more knowledge than the examination reveals.
But we should not assume that every weak explanation conceals strong understanding.
Sometimes the problem is language.
Sometimes it is organisation.
Sometimes it is incomplete knowledge.
Sometimes the assessment demands several abilities at once.
And sometimes the question itself makes it difficult to distinguish among them.
The educational task is to identify what is being measured and what the available evidence actually supports.
A fair examination should require students to demonstrate the intended competence.
A good teacher should help students develop both that competence and the ability to express it.
And a meaningful education should not confuse the absence of a polished answer with proof that no understanding exists.
Knowing, explaining, and demonstrating are connected abilities. They are not the same ability.
The better we understand that distinction, the more accurately we can assess learning — and the more effectively we can help students improve.
Tymur Levitin
Founder & Director, Levitin Language School
Language Learnings — US Branch
Global Learning. Personal Approach.
© Tymur Levitin
