As is often the case, I'd like to inject some "they do what over there now?".
In Thai culture, most (not all, but the vast majority) of people are legally named with relatively long names. My wife, SIL, BIL (SIL's husband), MIL, and FIL all have 3 syllable given names.
So, the kids always get a nickname. But, and here's where it's odd. The nickname is (a) chosen by the parents basically at birth, as with the legal name (b) mostly unrelated to the given name - definitely not just a shortened version; and (c) recently, there's a trend for it to just be an English language noun.
So my nearly-5-year old has a friend and kinder called "mammoth". I've heard first and second-hand accounts of kids called "ice cream" "England" "pizza".
This name is basically how the person will be referred to, by a significant portion of society for the rest of their life.
And no, we did not follow this practice. I did joke about using the name Riley, because dear god the mixed up Ls/Rs thing is not just a joke/stereotype.