Connection between Sound & Meaning ???

[j4mes_bond25]

Linguistically speaking, what, if any, connection might there be between the sounds of certain words and their meanings?

How has language evolved?

How does certain sounds turn into certain meanings?

PLEASE provide the answer in "layman's term", since this question was asked to me by a friend of mine & he'd expect me to be able to articulate my answer thoroughly WITHOUT any confusion.

[Tdol]

I've seen people suggest that the 'm' sound in mother/mum is suggestive of suckling.