It would be better to make children learn the sounds through the words because in most of the languages , more so European languages , it is the combination of letters that gives the sound. Of course , in all dictionaries , against European languages , it is mandatory in lexicography to mention IPA symbols next to the words as most of them have their origin in Latin. That's why some languages like French and German have uniformity and regularity in phonetics ( with exceptions clearly indicated as such).
Languages like English and Polish have absolutely irregular phonetics for the same letter in form with no logical reason or linguistic explanation.
It was this English predominance which made it mandatory to learn IPA for others to learn it.
For example the letter 'A' in April, Above, cAt have three different sounds indicated check dictionary with different IPA .
Similarly, even combinations of letters have weird phonetics in English d'oo'r, fl'oo'r, p'oo'r. whereas this anomaly is not there in French, German and Greek.
Children learn best through imitation.
Just utter some word and ensure some appealing connection. They will reproduce and recollect the word, sound meaning surprisingly the context too, often horrible pronunciation of non-native language ( it is justifiable).
Today there was a webinar on how to create a translation buddy.