The adding of the sigma may change the final consonant of the verb stem in the following five ways:
1. If after a palatal (k, g, or x)
[k, g, or x] + s ==> c
e@xw ==> e!cw I will have (note breathing change) . . .
a@gw ==> a@cw I will lead, bring . . .
2. If after a labial (p, b, or f)
[p, b, or f] + s ==> y
blegra gra 3. If after a dental (t, d, or q)
[t, d, or q] + s ==> s
pei pei4. If after a liquid (l, m, n, or r), (I call these “lemoners”—lmnr + s), the sigma is dropped and the w is accented with a circumflex. When a present stem ends in a double liquid consonant, one of them is sometimes dropped. The key is the circumflex over the primary ending instead of the normal acute accent. With the dropping of the sigma, there is a strengthening of the o and e connecting vowels so that the o becomes ou? and the e becomes an ei?.
I will remain.
I will send.
We will send.
You-all will remain.
5. If the stem ends in a sibilant (s, z), the sibilant is dropped and the sigma of the ending is kept.
Occasionally the future stem is totally different from the original present stem. Thus, as you learn more verbs, you should learn both stem forms. You just have to learn these tricky irregular verbs and keep your eyes open for them. The good part is that there are not too many of them.