15. A computer-readable storage device having instructions stored which, when executed by a computing device, cause the computing device to perform operations comprising: receiving, from a database, a plurality of stored speech samples of a same word for verifying a user; comparing each of the plurality of stored speech samples to each other, to yield a variance over time; and verifying speech received from the user as authentic based on the variance over time.
15. A computer-readable storage device having instructions stored which, when executed by a computing device, cause the computing device to perform operations comprising: receiving, from a database, a plurality of stored speech samples of a same word for verifying a user; comparing each of the plurality of stored speech samples to each other, to yield a variance over time; and verifying speech received from the user as authentic based on the variance over time. 20. The computer-readable storage device of claim 15 , having additional instructions stored which result in operations comprising prompting the user to say the same word.