Often we can hear a bird before we see it, so knowing the calls a bird makes allows us to know what to look for in terms of color, shape and location. When birding in new territories, it helps to know if the birds have a different language or accent than the ones to which you are accustomed. The Tufted Titmouse is one of those birds that can sound very different depending on the region in which it is found.
Gene Stratton-Porter perfectly described the call of the Titmouse in the Limberlost area in "Homing with the Birds": "Another extremely interesting small bird sometimes seen in the summer, but constantly with us in winter, is the titmouse. His soft, delicate plumage, his sharp crest, his bright eye, and his gaudy vest make him a beautiful creature, reminding me of the cedarbird in form. Clear and high, when food hunting around the Cabin and especially in spring, he calls: 'Hewit, hewit!' very seldom repeating the words more than once, each time making them clearly words, as I should speak them; at other times he drags his utterances. His song is high, clear, and beautifully musical in the winter woods, but so nearly like the wren's in bubbling spontaneity that I again confess myself unable to put it into syllables or give it sympathetic description."
Sibley's website contains a variety of recordings of Tufted Titmouse calls, beginning with the typical "peter-peter-peter" call. In different states and regions, the Titmouse has a very different call, sometimes sounding like a revved up version of "peter-peter-peter", other times sounding like the recording is being played at half speed, and other times sounding nothing like "peter-peter-peter" at all. Listen to the variety of the calls here: http://www.sibleyguides.com/bird-info/tufted-titmouse/the-under-appreciated-variation-of-tufted-titmouse-songs/
Adding to the confusion, in particular areas of Texas and Oklahoma there is an abundance of Tufted and Black-crested hybrids ("Current and Historical Extent of Phenotypic Variation in the Tufted and Black-crested Titmouse", Curry and Patten, 2014). The hybrids have their own interesting calls.
Another interesting difference to watch for in Tufted Titmice is the black patch on the forehead. Scientists have discovered that the larger the forehead patch on a Tufted Titmouse, the more likely he is to be the dominant male ("The Forehead Patch of Tufted Titmice: A Possible Status Signal", Moses and Ritchison, 2000).
The next time you see a Tufted Titmouse, take note of his unique call (or accent) and his forehead patch. Those two pieces of information might tell you more about that individual than you previously believed!