There are many of these ambiguous pairs: B/P, F/S, D/T, M/N, Q/U, ...
The end-to-end transmission can get really bad when you combine several different filter stages, such as a speaker's mouth being injured or obscured, a narrow channel like telephone or radio, noise, and a listener's ear losing parts of the spectrum.
As the sound transmission gets worse, you can get more rhyming ambiguities. Effectively, the consonants are lost in a bad channel and only the vowels come through. In an American English accent, I think these are the groups corresponding to different vowel sounds: A/H/J/K, B/C/D/E/G/P/T/V/Z, I/Y, O, Q/U, F/L/M/N/S/X, R. "W" stands alone with multiple syllables.
Depending on the kind of transmission problem, these groups can start to split apart into smaller subgroups based on which of their sonic differences make it through to the listener.
The end-to-end transmission can get really bad when you combine several different filter stages, such as a speaker's mouth being injured or obscured, a narrow channel like telephone or radio, noise, and a listener's ear losing parts of the spectrum.
As the sound transmission gets worse, you can get more rhyming ambiguities. Effectively, the consonants are lost in a bad channel and only the vowels come through. In an American English accent, I think these are the groups corresponding to different vowel sounds: A/H/J/K, B/C/D/E/G/P/T/V/Z, I/Y, O, Q/U, F/L/M/N/S/X, R. "W" stands alone with multiple syllables.
Depending on the kind of transmission problem, these groups can start to split apart into smaller subgroups based on which of their sonic differences make it through to the listener.