I became aware of the existence of this video from postings on the email list of VASTA, the (American) Voice and Speech Trainers Assn. Inc. Some of the commentators there were sceptical about the accuracy of the transcriptions.
I think that writing the Australian FACE vowel as [æi] is not unreasonable. I have to say, though, that superscripting the [i] symbol to show the less prominent part of a diphthong, as Philip Swan does in his [æi], is not an IPA-approved notation. (If you want to explicitly show “non-syllabic” in IPA, the correct diacritic is meant to be U+032F, a COMBINING INVERTED BREVE BELOW, thus [æi̯].) I am less than enthusiastic, though, about transcribing the Australian PRICE vowel as [ʌɪ], or as Swan has it [ʌɪ]. I would have thought that the first element was usually nearer to fully open cardinal [ɑ] than to open-mid cardinal [ʌ], let alone the Australian STRUT vowel. (Is this the baleful influence of Clive Upton’s unfortunate choice of symbol for the PRICE vowel in the OED/COD?)
I have no idea what the toddler is saying, or trying to say. Has anyone?
To disambiguate letter names in noisy conditions, articulatory descriptions would only work if both parties are well trained in phonetic terminology — which they normally aren’t. That’s why we use keywords: “S as in Sugar, not F as in Freddie”, or “sierra whisky alfa