Off Camera Lines
During the scenes where the Texans are fortifying the Alamo, and the Seguins ride in at top speed, an off-camera voice calls out, "Somebody comin' hell-bent for leather! Sinkin' spurs at every jump!" That is clearly the voice of Denver Pyle, who plays Thimblerig, a member of Crockett's band, who had not yet arrived at the Alamo.
Later in the movie, when Bowie and Crockett and a group go out at night to destroy the Mexican cannon, Denver Pyle is a member of the group. Travis finds out what has happened when an off-camera voice says that the sentry has been jumped, and another off-camera voice calls out, "Knocked me down! Tied me up! And some of them stepped on me and never a by-your-leave from a one of em!" Once again, the off-camera voice is clearly that of Denver Pyle.
It looks like Denver Pyle did a lot of off-camera line work for this movie. Hope he was paid extra for it.