8. A system, comprising: a data processing apparatus; and a computer storage medium encoded with a computer program, the program comprising data processing apparatus instructions that when executed by the data processing apparatus cause the data processing apparatus to perform operations comprising: receiving, for a query sequence, a word boundary likelihood that represents a likelihood that the query sequence terminates at a word boundary; determining, based on the word boundary likelihood, a time delay for delaying providing search results for the query sequence; determining that an amount of time since receipt of the query sequence exceeds the time delay, and in response: identifying search results responsive to the query sequence; and providing the identified search results.
14. The system of claim 8 , wherein the word boundary likelihood is based on a word boundary count and a non-word boundary count for the query sequence.