The word "speirs" is an alternative spelling of "spheres", and it's pronounced /sfɪərz/. In IPA phonetic transcription, the "s" at the beginning of the word is pronounced like "s" in "see", and the "ph" is pronounced like "f", as in "phone". The "i" is pronounced like "ee" in "beet", and the "e" is pronounced like "uh". The final "s" is pronounced like "z" sound, similar to "z" in "zebra". So, the correct pronunciation of "speirs" is /sfɪərz/.
The word "speirs" is derived from the Old English word "spyrian" or "spirian", which means "to inquire", "to explore", or "to spy". It is related to the Middle English word "spiren" or "spyre", which also means "to inquire" or "to search out". Over time, "speirs" emerged as a variant spelling of "spires", carrying the same meaning.