I can also relate to the late talking issue.
After 2 very early talkers my third child, who is now 2 years 5 months, has a VERY small vocabulary. He also does not talk at all around people he doesn't know. The expressive language that he uses right now is only recognizable by a DH and myself. When he does choose to talk it is usually a very garbled string of 5-6 words. He never did the simple 1-2 word sentences--went from nothing at around 23 months to 5-6 word strings of garbled speech. Examples are: "More milk please, Mommy!" with me only understanding one or two words. I have heard him say longer sentences like, "The kitty is sleeping in my bed" but since he doesn't pronounce the sounds correctly I mostly have to guess based on the amount of syllable and his pointing. Usually I try and repeat what I think he is saying in the form of a question so he can confirm his thoughts or try and correct me. So for the kitty statement I would say: "Oh, did you say that the kitty was sleeping in your bed"...DS2 then replies back to me "Yup."
The other area he really seems to struggle with expressive language is singing. He seems to know the words to songs but can't actually sing the tune. He rarely even attempts to sing now because it usually just comes out as a series of monotone grunts.
Since he has wonderful receptive language I am not really worried right now. I think if his speech is still very garbled by 3 years old he may need an early intervention referral because it may be more of a oral motor issue. I know he will eventually have much more expressive language. If he's anything like DS6 and DD4 I will wish he never started talking.
Obviously DS2 has not been tested but I know that his puzzle making ability, 1:1 counting (with garbled speech), and crazy sense of logic and humor will probably put him in the same category as his HG+ older brother.