I'm gonna try to make a super simple conlang like toki pona but the entire phonology is just the consonants that are easiest for early childhood speech development to use, a collection of mid-mouth vowels, and as many single-syllable words as possible, designed to use the smallest amount of energy to speak words.
p, b, m, n, w, t, d, h, ʔ (unwritten, only for preceding vowels without consonants)
ə <a>, ɪ <i>, ʊ <u>, ɛ <e>
@malkosh That's the main idea on the surface, but it's also to preserve as much air and energy as possible, which would be helpful in a lot of situations. Grammar will be the hardest part to work out, but I think using simple pre/suffixes to mark words and simple association via adjacent words would help simplify the grammar to a point that might be comfortable. It'll also be a very immediate-context-heavy language, not completely fit for heady or time-oriented conversations.