Foundation
Fundamentals
noun, の adjective
A foundation of foundations is a foundation. It is the fundamentals.
きそ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
基礎の日本語であれば教えられないこともないですが。
I could teach Japanese if it was just the fundamentals of Japanese.