Mrs, Miss and Ms are all considered to be abbreviations of the same word - mistress.

  However, there are different pronunciations of them:

1. Mrs. is pronounced as /ˈmɪsɪz/ or /ˈmɪsəs/. It sounds like "miss-iz" or "miss-us." The full word "Mistress" is rarely used in modern speech, so "Mrs." has its own pronunciation.

2. Miss is pronounced as /mɪs/. As written.

3. Ms. is commonly pronounced as /mɪz/, to rhyme with "biz". It is described as a neutral form for when marital status is unknown or irrelevant, but in practical use it tends to be used by divorcees or older, unmarried women.

Mrs, Miss and Ms are all considered to be abbreviations of the same word - mistress, so there are no official individual spellings of the three. However, there are different pronunciations of them:

1. Mrs. is pronounced as /ˈmɪsɪz/ or /ˈmɪsəs/. It sounds like "miss-iz" or "miss-us." The full word "Mistress" is rarely used in modern speech, so "Mrs." has its own pronunciation.

2. Miss is pronounced as /mɪs/. As written.

3. Ms. is commonly pronounced as /mɪz/, to rhyme with "biz". It is described as a neutral form for when marital status is unknown or irrelevant, but in practical use it tends to be used by divorcees or older, unmarried women.

Etiquette-wise, calling someone "mistress" is very out-of-date. Nobody uses this any more. It is still fairly common to address a younger girl as "miss", and older women as "madam" (or "ma'am"). It is not common though to refer to third parties by these. They are individual titles, so saying "ask any mister" is wrong.

Even though you might directly address a teacher as sir, miss, or madam, if referring to them collectively in general you would say "teachers". So, "ask any teacher" would be the right thing to say.