There are various accounts of the origin of the word teetotal, all more or less well documented, and the evidence indicates that it probably came into being both in America and in England, independently, within the space of a few years, early in the nineteenth century.
The earliest use, though, seems to have been American, in the form tetotally, the extra e being added later.
In any event, the word was coined in connection with the temperance movement to signify absolute abstinence from alcohol by emphasizing, through repetition, the initial sound of total, T-total.