This app looks great but....what is the 3rd sound in the word "wink" and "sink". The app seems to use the /n/ sound and not the /ng/ sound. Is this an error or a choice you've made. Also with the word "digs" some people will teach the end sound as a /z/ and not a /s/. Is this also another choice you've made?
The objective of the app is to teach beginning and struggling students basic decoding skills for reading. Although "n" makes a "ng" sound in "wink" (due to the influence of the velar "k" on the "n"), saying "n" instead of "ng" when sounding out the word is typically enough to 'trigger the phonological representation' of 'wink' (let's assume the student knows the word verbally), since the result sounds very similar...our speech systems make the necessary adjustments (adding assimilation) when we recognise and say the word. Same thing for words like "digs" (in which the "s" is influenced by the voiced "g"). We could have left out _nk and _gs words but we thought it was important to make the word library as large and flexible as possible (due to the customisation feature in the app, in which you can specify very precisely which word patterns to include). We do think those differences in pronunciation due to assimilation are worth teaching when teaching spelling, though, since when students segment the sounds they typically hear patterns like the "ng" in "wink" and the "z" in "digs".