I feel so dumb asking this, but I understand the idea of vowel ending stems and consonant ending stems for verbs, but is the root -gon or -agon? If it's -gon, then don't all verb stems end in vowels already? For example, is the stem of jaelagon jaela- or just jael-? Is sōvegon's stem sōv- or sōve-? It feels like it should be obvious but I'm pretty confused.
The -gon form is the (present) infinitive of a verb. If a verb's stem ends in a vowel, the ending is simply glued onto it: ȳdra-gon, ēdru-gon, nekto-gon, sōve-gon, sindi-gon. They take special endings when declined in relation to their stem vowel.
On the other hand, verbs with a consonant in the end of their stem take the infinitive ending -agon for euphonic reasons (ipradgon wouldn't be very possible). The -a- is not part of their stem though. Therefore one must take care in how a verb in -agon is declined; like ȳdra-gon or like iprad-agon? Such verbs will again use an extra -a- if needed, but are declined a bit differently.
eg. 3rd singular: ipradas vs. ȳdras, BUT 3rd plural: ipradis vs. ȳdrasi
Vowel stem verbs keep their vowel and take the ending on top or the vowel is united with the vowel of the ending either in a diphthong or a single vowel. (see Subjunctive, Future&Imperfect)
Is the 3rd plural a good indicator of the group ? For exemple the verb "to fear", is it "Izūgon" or "Izūgagon" ? Izūgon seems right but the 3rd plural is Izūgis so i guess the infinitive is Izūgagon ? If a Duolingo team member pass by, is it possible to add the infinitives of the verbs in the dictionary ? Some are there but many aren't unfortunately.