Is it supported by evidence that girls usually start talking earlier than boys? (It was clearly so in my children.)

I'm not certain whether I agree with their arguments, but the data to your core question are well summarized here:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6509633/

Quote

Beside the fact that girls have a well-documented advantage in early language development, almost all developmental disorders primarily affecting communication, speech, and language skills are more frequent in boys. <...> We argue that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men.

 

Iirc, girls optimize connections in the brain a bit faster than boys, leading to earlier development in several areas.

25 minutes ago, Phi for All said:

Iirc, girls optimize connections in the brain a bit faster than boys, leading to earlier development in several areas.

I only started reading this:

 

2 hours ago, iNow said:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6509633/

and saw references to the differences in other communication skills and behavior.

Are there other areas of such differences, not related to the communication?

2 minutes ago, Genady said:

I only started reading this:

Is this the same study or a different one? https://pubmed.ncbi.nlm.nih.gov/24343892/

Quote

First, our findings showed that the number of fiber tracts, small-world topology, and modular organization remained largely stable despite a substantial overall decrease in the number of streamlines with age. Second, this decrease mainly affected fiber tracts that had a large number of streamlines, were short, within modules and within hemispheres; such connections were affected significantly more often than would be expected given their number of occurrences in the network. Third, streamline loss occurred earlier in females than in males.

 

4 minutes ago, Genady said:

Are there other areas of such differences, not related to the communication?

These studies seem to indicate that the streamlining of connections in the brain reorganizes their functions to make them more efficient. Girls seem to mature faster than boys, probably because they're able to focus a bit better owing to reduced pathways leading to the information they need. It sounds like girls find the highways in their brains while boys are still driving around on back roads. 

33 minutes ago, Genady said:

I only started reading this:

 

and saw references to the differences in other communication skills and behavior.

Are there other areas of such differences, not related to the communication?

With regard to differences we should differentiate aspects related to development/maturation, which does seem to have measurable sexual dimorphism, to structural aspects. The knowledge on the latter and especially the question whether sex dimorphism in human brains actually exists is an everchanging discussion, which is highly dependent on our technology to measure these differences. In mature humans, the effect size seems to diminish, the more we measure. A fairly recent meta-analysis argues that most differences described are related to brain size rather than any functional differences, for example. This is, of course, not the question in OP, but I thought it might be worthwhile to mention, in case the discussion drifts into that area.

20 minutes ago, Phi for All said:

Is this the same study or a different one?

A different study.

Interesting reading.

7 minutes ago, CharonY said:

worthwhile to mention

Certainly.

If not structural dimorphism, what these differences in development are attributed to? Gene activations, chemistry?

Developmental biology is not really my forte, but a lot of developmental timing is related to humoral control (which affects gene expression), which is also dependent on factors such as nutrition. So there is a bit of a complex interplay and I am actually not sure whether there is simple model explaining these differences somewhere.

2 hours ago, CharonY said:

a lot of developmental timing is related to humoral control (which affects gene expression), which is also dependent on factors such as nutrition. So there is a bit of a complex interplay and I am actually not sure whether there is simple model explaining these differences somewhere.

Yes, here is the conclusion of the review article linked by @iNow above (Sex differences in early communication development: behavioral and neurobiological indicators of more vulnerable communication system development in boys - PMC (nih.gov)

Quote

Many studies clearly showed the correlation between sex hormones and developmental outcomes. Moreover, anatomical, histological, and brain activation differences in the speech and language brain areas were also documented. Overall, it seems that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men. The specific mechanisms that lead and contribute to the development of this advantage are yet to be fully discovered.

 

Edited February 7, 20232 yr by Genady

14 hours ago, Genady said:

Is it supported by evidence that girls usually start talking earlier than boys? (It was clearly so in my children.)

 

11 hours ago, Phi for All said:

Iirc, girls optimize connections in the brain a bit faster than boys, leading to earlier development in several areas.

Is that learned/taught or innate?

Edited February 7, 20232 yr by Intoscience
spelling

3 hours ago, Intoscience said:

 

Is that learned/taught or innate?

Seems rather biological than social, especially if hormones are a factor.

It could've been social if others communicated with baby girls somewhat differently than with baby boys, but is it so?

3 hours ago, Intoscience said:

Is that learned/taught or innate?

Definitely!

19 minutes ago, iNow said:

Definitely!

Interesting!