…的话【de huà】

的话 goes at the end of a condition and marks it as "if". It belongs to speech, and can stand alone or close a clause that opens with 如果 or 要是.

The result half often has 就 before its verb, as with 如果.

的话 closes the condition

It goes at the end of the "if" half, never at the start.

• × 的话你有时间，我们去吧 → 你有时间的话，我们去吧
• × 你的话有时间 → 你有时间的话

Short fixed uses

的话 also turns a word or two into a condition: 不然的话 "otherwise", 这样的话 "in that case", 可以的话 "if possible".