The major mnemonic system encodes digits as consonant sounds in order to make words out of numbers. The allotment of noises might seem inefficient at first.Some numbers get more sounds than others because some noises belong to clusters of related sounds and some do not. Theres no such thing as an unvoiced L noise, so 5 gets L and no other sound. 8 gets P and B due to the fact that these are unvoiced and voiced variations of the very same sound.
For more on IPA, see the Wikipedia IPA assist page.
Here are the IPA symbols above that do not correspond to English letters.
Since some sounds belong to clusters of related noises and some do not, the allowance of noises may seem ineffective at first.Some numbers get more noises than others. For instance, theres no such thing as an unvoiced L sound, so 5 gets L and no other noise. 8 gets P and B because these are unvoiced and voiced variations of the very same sound.
If youre not familiar with the concept of voiced and unvoiced singing noises it might appear arbitrary that, for example, the F and V sounds both translate to 8, or that the S and SH sounds map to various numbers, 0 and 6 respectively.
The major mnemonic system encodes digits as consonant sounds in order to make words out of numbers. The system operates in regards to noises, not spellings, and so some of the symbols listed below are not English letters but rather IPA symbols  More on the system here.
When you understand each digit gets one consonant group, the allowance is more uniform than it appears at first.
The current episode of The History of English Podcast goes over the history of pronunciation modifications in the Elizabethan duration. The episode has a lot to say about the connections in between voiced and unvoiced pairs of consonants, and the scenarios under which a consonant may alter from voiced to unvoiced and vice versa.
 Here are the IPA symbols above that do not represent English letters.|—–+———|| IPA|Example|| —–+———|| ð|THis|| θ|THistle|| ŋ|siNG|| ʤ|Container|| ʧ|CHurCH|| ʃ|SHoe|| ʒ|corsaGe|| —–+——— |