There is much lexis that has the features of Ossetic -European isoglosses.
The dictionary is constantly being updated so as to include new lexis, this has always happened and will continue to do so.
In any kind of writing you should have a sense of appropriate register or special lexis.
But most have some special lexis - they make choices of vocabulary that reflect their ideas about school or education.
Then I gave them some handouts I had prepared so that they could practice the written form of new lexis and grammar.