Self Study
Self Education
noun, する verb, の adjective
You are alone in your study. You are studying on your own. This is self study.
どくがく
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
インターネットの普及によって、独学で外国語を勉強することは昔よりもずっと簡単になった。
Due to the spread of the Internet, it’s become much easier to learn other languages through self-study nowadays.