Not good for American English
Not suited well for American English phonemes. And even if you choose the American accent option, the only thing that changes is the way words are pronounced and their transcriptions, but the phoneme buttons remain British (RP). And moreover, when you click a phoneme button that exists in American, it will show examples of words in which that phoneme is present in a word in British, but if it differs in American, it will still be shown as if it’s present there. Example: “aunt” is shown when you click /ɑː/, since indeed in RP it is pronounced as /ɑːnt/, but if you have American selected as the accent option in the settings, the word will still be shown as an example in the phoneme, but will be rightly spelled as /ænt/ in GA. However, this doesn’t make sense since you’re in the phoneme /ɑː/ section. Also, vowel length isn’t phonemic in American. Overall, this app is probably fine if you’re interested in British phonetics, but won’t work well if you are interested in American English, especially when it comes to vowels, since it doesn’t even have some American phonemes, such as diphthong /oʊ/.
