V1[]
This function is not in SmileBasic V1.
V2[]
In the Japanese release of SmileBasic V2, TALKCHK() returns TRUE if the speech synthesizer is currently active (due to a TALK command), and returns FALSE if the speech synthesizer is inactive.
In the North American release, TALKCHK() always returns FALSE.
V3[]
No information on SmileBasic V3.