The spelling of the word "mouth Steinway" may seem peculiar, but it can be attributed to its origins in German. In IPA phonetic transcription, it is pronounced as /maʊθ ˈstaɪnweɪ/, with a "th" sound rather than "t", and "ei" pronounced as "eye". "Mouth" refers to the opening of a musical instrument, while "Steinway" is the famous brand of pianos. Thus, "mouth Steinway" represents a specific type of piano with a unique characteristic in its design.