How do you choose words to ensure that a sentence will be a tongue-twister? What are the criteria for determining which words will be a tongue-twister from an initial word you chose randomly? I don't understand the exact process, is it just choosing a word that sounds similar or is the process more involved?
Generally the phrase should be alliterative or feature rapid repetition of similar sounds. The go to example I think of for tongue twister is "Peter Piper Picked a Peck of Pickled Peppers" which contains only two words, neither prominent, that do not start a "Pi" or "Pe" sound. Additionally, of the prominent words, there are prominent repeats of the letters "C, E, K, I, P, R" found in every word with only two letter's (L and T) in only one word.
Other tongue twisters may not do this but may be long strings of disjointed syllables such as the famous phrase from Mary Poppins "Supercalifragilisticexpialidocious", though as the song demonstrates, it's only a tonge twister if you take it on quickly without first breaking it down in your head. Mary Poppins not only prominently enunciates the words at different speeds, but even reverses the syllables with ease (dociousaliexpilistic-fragilcalirupus) which she claims is saying the word backwards but only the "super" part is reversed (Rupus), she just reverses the order of every syllable's progression.