I have some experience on the autism front. There is a fairly famous autistic person by the name of Temple Grandin, she couldn't speak much when she was a child.
Intelligent Autisitics divide / overlap two rough categories, the verbally adept, and the visually adept. The verbally proficient and intelligent autistic kid at two will talk the hind leg off a donkey using words unexpectedly large for his/her age, though will use them in a mimicked but possibly misunderstood context. Eg (indignant tone) "In future you are stepping on my foot". The words "in future" came from the "I'm annoyed with you" context but without the understanding.
Visually adept (aspergers) kids don't do so well with words but do really well with hieroglyphics or pictures - so you have a chart of pictures with different ideas represented eg food, drink, school, book, toilet, bath, bed time, etc etc.
But for your son, rebec, it could be something completely different. Who knows. I do think the earlier the experts come up with communication strategies for your son, the better for his future socialisation skills - it's hard to get along with other people if you can't or won't talk.
But try lots of different things and approaches, and experts until you find the one that works. A lot of strategies that work well for autistic/aspergers work well for other kids eg highly structured routines, plans that are announced ahead of time (with the added provisio that they may be changed) and a lot of visual reminders and cues and lists of things to take / do for each occasion.