These were the names of the sons of Israel (Jacob) who came with him to Egypt along with their families: Reuben, Simeon, Levi, and Judah; Issachar, Zebulun, and Benjamin; Dan and Naphtali, Gad and Asher. Jacob had 70 descendants there, including Joseph who was already in Egypt.
Eventually Joseph and all his brothers and all that generation died. However, the Israelites had many children and their numbers increased rapidly. In fact there were so many of them that they became very powerful—the country was full of them.
Then a new king came to power who didn't know anything about Joseph.* It is thought to refer to a different Egyptian dynasty. He conferred with his fellow Egyptians and said, “Look at these Israelites—there are more than them than us, and they're more powerful than us. 10 We've got to make plan to deal with them before they become so many that if there's a war they'll side with our enemies and fight us, and flee the country.”
11 So the Egyptians made them do forced labor and put taskmasters in charge of them. They used them to build the storage towns of Pithom and Rameses. 12 But the more the Israelites were mistreated, the more they grew in numbers and spread out—and the more the Egyptians detested “Detested” or “feared.” them. 13 The Egyptians worked the Israelites brutally, 14 making their lives a misery. They made them do hard labor, building with mortar and brick, and all kind of heavy work in the fields. In all of this hard labor they treated them brutally.
15 Then the king gave orders to the Hebrew midwives, Shiphrah and Puah. 16 He told them, “When you assist the Hebrew women during childbirth, if you see it's a boy, kill him; but if it's a girl, let her live.” 17 But because the midwives revered God, they didn't do what the king of Egypt had ordered. They let the boys live as well.
18 The king of Egypt called the midwives in and demanded to know, “Why have you done this— letting the male children live?”
19 “Hebrew women aren't like Egyptian women,” the midwives told Pharaoh. “They give birth more easily—they have them before we midwives arrive.”
20 God treated the midwives well, and the people increased in number so there were even more of them. 21 Because the midwives revered God, he gave them families of their own.
22 Then Pharaoh issued this order to all his people: “Throw every Hebrew boy that's born into the Nile, but let every girl live.”

*1:8 It is thought to refer to a different Egyptian dynasty.

1:12 “Detested” or “feared.”