Language and Non-standard speech

Language noun - The stock of words, pronunciation, and grammar used by a people as their basic means of communication.

Non-standard speech and language are semantically related. In some cases you can replace phrase "Non-standard speech" with "Language", this terms are similar.

Non-standard speech noun - Speech that differs from the usual accepted, easily recognizable speech of native adult members of a speech community.

Language and non-standard speech are semantically related. You can use "Language" instead a noun phrase "Non-standard speech".