A learner who knows "decide" may still write "We need a decide by Friday." The meaning is available. The required noun is missing. This article is for a university student in Taipei who recognises academic words in readings and then stalls while drafting a 650-word report. Treat derived forms as separate pieces of usable knowledge. Learn the two relatives demanded by the next task, practise them in sentences, and leave the rare members of the family for later.
One family, uneven knowledge
Word families group a base with related forms. Decide, decides, decided and deciding carry grammatical inflections. Decision and decisive involve derivation, which can change word class or meaning. Dictionaries make the family look tidy. Learner knowledge seldom arrives as a complete table.
Norbert Schmitt and Cheryl Boyd Zimmerman asked 106 non-native-speaking university students to produce noun, verb, adjective and adverb forms for 16 prompt words. Complete knowledge of all four forms was uncommon. Learners typically produced two or three, with adjective and adverb forms causing more difficulty. The 2002 study used educated learners and a prompted written task. It did not measure every kind of spontaneous speaking or reading knowledge.
Emi Iwaizumi and Stuart Webb later compared 23 L1 English speakers with 107 L2 learners across vocabulary levels from 1,000 to 5,000. Participants tried to produce derivatives for 90 headwords. L2 performance differed by vocabulary level; learners who had mastered the 3,000-to-5,000 levels produced a similar number of derivatives to the L1 group on this decontextualised recall test. The study shows that broader vocabulary and productive derivational knowledge travel together to some degree. Its design does not tell us that memorising suffix charts caused the difference.
Teachers should also separate knowledge of a spelling pattern from control of a particular word, since a learner may understand that -ity often makes nouns and still hesitate over reliable, reliability and the changed stress pattern.
Knowing the verb conserve gives a clue to conservation. The noun still brings its own stress, spelling, countability pattern and the phrase conservation of energy in context.
Recognition hides the gap
In a reading, the sentence supplies help. "The committee reached a decision" places an article before the target and a verb before that. Even if decision is only partly known, syntax and topic narrow the options. A blank page removes those cues. The writer starts with "The committee decided" and may have no quick route to the noun needed after "a."
Beatriz González-Fernández and Norbert Schmitt tested 144 Spanish learners of English on recognition and recall across form-meaning links, derivatives, multiple meanings and collocations. Recognition developed before recall across the components, and the two behaved as distinct kinds of mastery. Their Applied Linguistics study helps explain a common frustration: a word can look completely familiar in an article and remain unavailable in a presentation.
Do not count that as failure. It is a measurement result. Recognition says the incoming form can reach meaning. Recall asks the learner to travel in the other direction under pressure.
Choose relatives by task
Teaching every visible relative at once creates impressive notes and weak retrieval. The family around "analyse" may include analysis, analyst, analytical and analytically. A first-year student preparing a lab report probably needs analyse, analysis and analytical. A learner preparing for a finance interview may need analyst as well. Analytically can wait unless the source material keeps using it.
I would rather teach three members deeply than display nine and test only their spelling. Frequency matters, yet task frequency matters too. "Reliable" and "reliability" may appear repeatedly in an engineering report even if a general word list ranks another relative higher.
Build a small family card with four fields:
| Job in the sentence | Form | A real frame | Learner's sentence |
|---|---|---|---|
| action | analyse | analyse the survey data | We analysed 237 responses. |
| thing or process | analysis | the analysis indicates | The analysis indicates two clusters. |
| description | analytical | an analytical method | We used an analytical method from Chen et al. |
The "job" column matters more than a label copied without understanding. After identifying the noun, remove the card and complete "Our ___ covers 237 responses." Then change the sentence: "We ___ 237 responses." The switch forces productive choice between analysis and analysed.
Context is part of recall
Iwaizumi and Webb later compared contextualised and decontextualised derivative recall with 21 L1 and 107 L2 English speakers. Contextual cues helped recall, with larger benefits for native speakers and L2 learners who had greater vocabulary knowledge. Token frequency mattered more on the decontextualised test. The 2023 report gives teachers a reason to practise word families inside sentences while still checking recall with some support removed.
Use a four-turn exercise. The teacher gives "This policy will ___ attendance." The learner chooses affect. Next comes "We measured the ___ on attendance," which calls for effect. Then the learner writes a workplace sentence with effective. On the final turn, the prompts disappear and a partner asks for the three forms plus one sentence each.
Irregular and semantically distant relatives need separate care. "Hard" and "hardly" look closely related yet carry very different meanings. "Industry" and "industrious" no longer form a useful everyday pair for many tasks. A suffix rule cannot rescue a learner from those histories. Check a learner dictionary and a corpus example before adding a clever-looking relative to the card.
Connect form to company
Derived forms also have preferred neighbours. A decision can be final, difficult or unanimous. People reach, reverse and postpone it. Learning the noun without those companions leaves the sentence half built. Our article on recording the words that travel together explains how collocations turn an entry into usable material.
When a learner retrieves decision together with reach a decision and decision on the budget, the noun arrives with enough grammar and company to enter an email instead of remaining an isolated table entry.
Keep the workload narrow. For each base word, add at most two derived forms and one frequent phrase for each. Review them by changing the grammar of one message, not by reciting a suffix list:
We decided to postpone the launch.
The decision to postpone the launch came after Tuesday's test.
Tomorrow, open the report draft that stalled. Find one repeated base word, choose the noun or adjective the next sentence requires, and write two versions before adding anything else to the list.