I was watching a program talking about a Japanese rapper (don't know if this is common to many rappers, or features in English rap, though) who often uses one rhyming technique of matching vowel patterns on consecutive lines. Assonance is repeating the same sound, but this might be like:
The cat spend nights on fun things
The rams fed pills stop butting
The program, aimed at the casual viewer, just used (in Japanese) something like "He used the same vowel pattern on each line", but is there a proper name for this technique?