15. A computer storage medium encoded with a computer program, the program comprising instructions that when executed by one or more 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.
15. A computer storage medium encoded with a computer program, the program comprising instructions that when executed by one or more 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. 16. The computer storage medium of claim 15 , wherein the time delay is inversely proportional to the word boundary likelihood.