How to read piano English?

Generally speaking, those ending in O, S, X, ch, sh are added with es at the end, such as potatoes and tomatoes. However, some loanwords or abbreviations ending in O only add S in the plural form. If there is a vowel before the letter O, only add S.

Because piano is a foreign word, so add S directly.

The width of the piano is different.

These pianos have different widths.

English irregular plural forms and their changing rules

1, most nouns ending in f or fe are converted into ves in the plural form, such as calf → calves.

2. Change "us" into "A" (applicable to technical terms): corpus → corpus.

3. Turn "we" into "I": alumni → alumni.

4. change "um" into "a": addendum → addendum.

5. Words ending in "ex" or "ix" are changed to "ices": apex → apecs → apex.