The importance of scaffolding your definitions

In terms of vocabulary that learners (any learners) are presented in any content based mainstream lesson, we can distinguish between content-obligatory and content-compatible vocabulary. 

Content-obligatory vocabulary is the sort of vocabulary necessary to master the objectives and key concepts of a lesson. These words and phrases are directly supportive of what you are teaching in your lesson and are disciple-specific.

Content-compatible vocabulary is expected to appear in your talk, it complements and supports the introduction of content-obligatory language, but expands your learners’ language learning beyond the immediately academic language confined to your discipline; it’s vocabulary that is less specialised, but, nonetheless, still important to your subject.

Here are some examples of the two, taken from this Coursera course on lesson planning for ELLs.

Content-obligatory vocabularyContent-compatible vocabulary
Maths: multiply, circumferenceMaths: circle, measure, numbers
Social studies: continent, electoral collegeSocial studies: president, mountain
Science: atom, mass, moleculeScience: cycle, weather
Geography: erosion, earthquakeGeography: shift, land

Let’s turn to practical classroom-based matters now, keeping this distinction in mind. Many of you might have translated keywords for your English language learners – I am specifically referring here to new to English learners, who have been in the country for less than a year, perhaps, rather than more advanced EAL learners. Perhaps you have used Google Translate for this, given an iPad to a learner or put translations on your board or PPT next to their original English keyword equivalents.

I argue that that’s not really what you should concern yourself in the first place, i.e. it is actually the content-compatible language and vocabulary that you should focus more on and not just translate the obligatory vocabulary for your EAL students. Why? – well, I list the reasons just below:

  • Your keywords are very likely the words new to everyone – the new stuff of the lesson – if so, no one knows the new words! Think about it:
    • If you are a Science teacher and you introduce the concept of photosynthesis to your learners (and doesn’t “photosynthesis” sound alien, like a different language, anyway?), not a single student knows what it means.
    • If you teach Geography and this is the first time you speak about the concept of “erosion”, nobody in your class, monolingual English or any bilingual (emergent or not) knows what this means – this is a new word for all.
    • An English teacher? Everyone’s new to what “a soliloquy” or “a metaphor” is.
  • In the course of a lesson, how do you introduce these “metaphors”, “erosions” or “photosyntheses”? Well, you use the English language:
    • This will necessarily include the content-compatible language/vocabulary.
    • This will be understood by the native English speaking children, but might potentially leave your EAL learners in the cold – this is what they need to learn.

To have just a tiny glimpse of what I mean by this in practice, let’s examine the following example (this is originally available at

On the left, you can see a diagram of the different layers of the Earth. 


1 – Do you think the concepts “crust”, “mantle” or “outer core” and “inner core” need translating here? If I wrote these in Bengali and taught you these, with some practice, would you be able assign the label to the relevant part of the image?

2 – Is there any point translating these terms, then?


I am kind of hoping we agree that the answer to the first question is a resounding YES, and to the second – a resounding NO. Whilst there is no denying that bilingualism is an asset and should be taken advantage of at schools, you also do not want to engineer a situation where your EAL learners become convinced that where there is no dictionary, there is no way. 

The only words that are not content-obligatory in the image above are “outer” and “inner”. This is because, clearly, they are less confined to the subject of Geography and are used more widely (e.g. inner/outer circle).

Let us now examine which words or lexical/grammatical elements might need explaining when an explanation is given in the lesson of what the crust, mantle and core actually are. This comes from the same linked-to webpage above, but I am sure you can see yourself or another teacher saying these very words in a Geography lesson:

What are the three layers the Earth is made of?


CrustThe crust is the outer layer of Earth. It is about 18 miles thick. It is the part we live on.
MantleThe second layer is called the mantle. It is about 1,800 miles thick.
CoreThe inner layer is called the core.

Here, you might choose to focus your differentiation on the words in the definitions . Whilst the learners might be able to locate mantle, core and crust in the diagram (so, again, no point translating this), if this is entirely new content that you’re presenting, in order for them to internalise the additional definition-based information, you need to make the content-compatible words more accessible. 

These words are here: inner, outer, layer, thick, second (and how it’s different from “first”), called.

Several options here in terms of what to do:

  1. Simplest: translate the above (the first set below is Polish; the second: Lithuanian)



You might choose to follow up such an activity by instructing your EAL learners to write the definitions in their language. Who cares if you don’t understand the language? – if they can prove to themselves that they understand these concepts and can have a record of this, this is just as good as doing this in English. It’s a powerful motivator to your learners, showing them in no uncertain terms that their teacher respects their linguistic identities, that what they’ve learned before in life matters and that they haven’t been reduced to English language learners only just because they moved to a new country. 

2. Use images and get your learners to match up the words to the pictures.

3. Make flashcards (or get them to make flashcards for these words) or play a memory game of Pelmanism with these.

4. As a possible follow-up to such introduction:

  • make a gap-fill from the definitions above, but: remove the content-compatible words and replace them with the images – do they remember the English words now?

5. You could use substitution tables for these as well:

I have given the content-compatible vocabulary boxes the green colour to show what we are focusing on here. Every time, the students need to write the correct word to fit the context of the sentence and show their understanding. You could, of course, use the same images as before, and get the students to write their sentences, but replace the images with the English words.

Do remember that any substitution table can be subsequently cut up and you could get your learners to rearrange it to its original form – this focuses your learners’ thinking not only on the lexical elements but on the word order of the English language.


Summing up

Considering how to scaffold the content-compatible language in your lessons should take priority. The content-obligatory vocabulary is certainly what you want and need to teach; however, if you do not take care of the building blocks – the content-compatible language – you won’t even start building anything. If you don’t know the alphabet, you can’t make a word. If you don’t have bricks, you can’t build a wall. If your EAL learners cannot access the language of your definitions when you explain concepts to students, they won’t be able to access your content.

Simples. Start having content-obligatory and content-compatible language objectives when planning lessons.

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