Solution to the Sequence

The first term is 1

The second term 11 describes how you pronounce the first: one one

The third term 21 describes how you pronounce the second: two ones

The fourth term 1211 describes how you pronounce the third: one two and one one

The fifth term 111221 describes how you pronounce the fourth: one one, one two, and two ones

So the next term is 312211