Students will acquire most of the grammatical “function” words naturally as they read and listen to the target language. I wouldn’t overtly teach these words as a unit, but it can be helpful to keep them in mind to be sure you are using the most useful ones–especially if you are not a native speaker.

 

 

You can find a set of Spanish function words here (they are about the same in every language). Teaching these as lists would be contrary to the quote above. I wouldn’t use these as a graded test, but from time to time as an indicator of what students are acquiring through the school year, they can be useful. They would be more of a test of the teacher’s progress in teaching than the students’ progress in learning the language.