We had similar situations (we're 3.5 now), our kid wasn't talking as much as others at certain age categories, but he knew ABC very well in multiple languages,

We had similar situations (we're 3.5 now), our kid wasn't talking as much as others at certain age categories, but he knew ABC very well in multiple languages, he could count to 100 easily and do basic addition at the very early age, while others were better at talking. Whenever someone was saying "by now he should be doing this and that", I would respond that it's not the race[sometimes more harsh than that, so that the discussion would be over immediately]. We do not follow the so called "recommended milestones", same as we do not follow guidelines of the age recommendation on the back of the toys.