What does Genesis 30:12 mean?

Leah and her younger sister Rachel are both married to the same man: Jacob. Only Rachel was an intended bride, however. After working seven years for the right to marry Rachel, Jacob awoke the morning after his wedding to find that the girls' father, Laban, had tricked him by switching in Leah (Genesis 29:18–30). Though Jacob was allowed to marry Rachel almost immediately, for another seven years of indebted labor, he understandably never showed love to Leah (Genesis 29:31). Partly in response to this, God allows Leah to bear children for Jacob while Rachel remains barren (Genesis 30:1). Desperate and angry, Rachel produces two sons by using her servant, Bilhah, as a proxy mother (Genesis 30:1–8). Not to be outdone, Leah, who had recently stopped bearing children (Genesis 29:35), uses the same strategy and obtains a child. Leah's servant girl Zilpah could also be described as one of Jacob's two slave wives. Any children born by her will legally belong to Leah and Jacob.

Now Zipah bears to Jacob her second boy, his eighth son. This child will be named Asher, to reflect Leah's happiness.