But this is not the case. The sound added to the final f is the sound of z, not that of s.
And the plurals are sounded loavz, wivz (wivez, weivz).
Furthermore, the sound of the final f is changed to that of v; in other words, the first of the two letters is accommodated to the second, in violation to the rule of § [199] b.
Can this be explained? Perhaps it can. In the Swedish language the letter f has the sound of v; so that staf is sounded stav.
Again, in the allied languages the words in question
end in the flat (not the sharp) mute,—weib, laub, calb, halb, stab, &c. = wife, leaf, calf, half, staff.
This makes it probable that, originally, the f in wife, loaf, &c. was sounded as v; so that the singular forms were wive, loav.
If so, the plural is perfectly normal; it being the singular form on which the irregularity lies.