Ibn Ezra on Exodus 1:19/אבן עזרא על שמות א׳:י״ט

1AND THE MIDWIVES SAID UNTO PHARAOH. We have not violated your command because the Hebrew women are not like the Egyptian women; they have greater vitality. The yod of the word chayot (lively) in For they are lively does not have a dagesh. This is correct Hebrew usage. Compare, davot (ill), ravot (satiated), and alot (giving suck) in the flocks and herds giving suck are a care to me (Gen. 33:13). However, the yod in the word chayyim does receive a dagesh because chayyim is an adjective. Compare, ve-nitpesem chayyim (we shall take them alive) (II Kings 7:12) in which the yod in chayyim (alive) is like the yod of ha-ivriyyim (the Hebrews) in the God of the Hebrews (Ex. 3:18). The word chayyim (life) also receives a dagesh when it is a noun, as in etz chayyim (a tree of life) (Prov. 3:18). Similarly, the tzadi of tzitzim (flowers) in and open flowers (II Kings 6:18) receives a dagesh.

2AND ARE DELIVERED. Ve-yaladu (and are delivered) is a feminine perfect. The third person perfect has the same form in the masculine and the feminine. Compare, tavu (did spin) (Ex. 35:25) and tzave’u (did service) (Ex. 38:8).