By the way, in speech.c there are lines below:

	// Add a constant to allow for very small buffer_length
	n_event_list = (buffer_length*200)/1000 + 20;

where + 20 is probably crutch for zero sized buffer_length coming from above. I tested, that it passes all checks without it, but left it, because was not 100% sure. (And I was not 100% sure because with previous implementation minimum for n_event_list was 20, but with min_buffer_length 60 and n_event_list without + 20 it would be 12.)