I need an engineering elective for first term. I wanted to take Lingquistics 1A03 which sounded really interesting but it is full. Here is all the explanation I could find online of 1Z03/1ZZ3..

It is intended for students with no prior knowledge of linguistics who wish to acquire an understanding of the structures which make the speaking, understanding and writing of English possible. We will learn how to analyse the structural principles on which words are combined to create meaningful utterances. This will involve the study of syntax (the relationship between words), semantics (the roles that the words carry out) and pragmatics (the conventions for the use of language in English-speaking communities).

Is this for people with English as a second language or something? It seems really vague and basic compared to the 1A03 description.

Both channels, 1A03+1AA3 or 1Z03 +1ZZ3, will give you an introduction to Linguistics, and would be appropriate prerequisites to further study in the field. The A courses are more traditional, in that there is an assumption that participants have some experience or future with other languages. The Z courses focus on English, and probably would be a better choice for one not intending to continue in Linguistics. I believe the Z courses are offered in the evening, which might be a better timetable fit for some people. I believe the Z courses have been taught by Dr. George Thomas, an emeritus professor in the department. Very approachable, very pleasant manner. He takes time to explain things in whatever detail is required. His assignments, testing and marking have been quite fair in the past, almost generous.