Each pitch determines how it should sound ???

[jancivil]

I would say, though, that the minor third for calling MAMA or after your child in the distance is universal and probably has something to do with the human body.

[vurt]

MAMA

there is a theory, that despite parents and the "awww he/she said mama/dada"
that babies are in fact trying to get to "mine mine" or "that that" as in "give me that", obviously i wont mention this theory to my son and his gf at the minute


also, i wish i knew who was paying people to try to translate what babies are saying?

they can be amazing though, ive often seen two or three toddlers together.
one will be chunnering away in that "wahahwoowah" speak they do, then stop, another will reply similarly, then stop, then all 3 burst out laughing as one.
so they know or at least seem to know whats being said.
i reckon theyre planning stuff.

[Musicologo]

No one is going to think "ooh, happy times!" when hearing a Psycho-shower-scene-esque train of minor seconds, right?

https://www.youtube.com/watch?v=34ZHJj0lW0I

Some cultures actually do happy times over a train of minor seconds and clustered dyads.

But, in relation to the OP question, I'd say the best theory so far I've seen is the one that relates the pitch of normal speech with the pitch of sung speech. Pat here also mentions Leonard Bernstein idea that in all cultures people whine and tease in minor thirds.

https://www.youtube.com/watch?v=jSOd7HK0E78

Let's say that when you talk normally and are telling the truth the meaningful sylables hoover around Eb2. Then if you build your melodic line with the key words around that you'll sound truthful and convincing, if you build your melodic line with the key words around Ab2 you'll sound preachy, if you build your melodic line with the key words around Bb1 you'll sound agressive, if you build your melodic line with the key words around C3 you'll sound desperate, etc..

It's always in relation to your "normal" speaking voice. Pick your sung pitches aproximating the tone, character and intention when you talk.

[I. C. H. Beatbuster]

OK, most of what has been answered here I do not understand. One thing seems to be certain though. There is no answer for that. But I have learned something again, if only a little and a very good tip where I can find answers for people like me.
I thank everyone and for me the topic is over.