Speech and thought combine to make verbal thought or language.
To understand what happens next, one must consider how Vygtsky viewed language. Before language, the child had two developing skills: speech (a motor act) and thought (a non verbal process of problem solving).
Speech without thought (A) was just a motor act. An example would be a child repeating the phrase, “Sing a song of six pence, a pocket full of rye.”
SPEECH + THOUGHT = VERBAL THOUGH = LANGUAGE
NOTES: And yet, some more Vygotsky theory.