Correct spelling for the English word "underbrigadier" is [ˌʌndəbɹˌɪɡɐdˈi͡ə], [ˌʌndəbɹˌɪɡɐdˈiə], [ˌʌ_n_d_ə_b_ɹ_ˌɪ_ɡ_ɐ_d_ˈiə] (IPA phonetic alphabet).
The word "underbrigadier" does not have a specific etymology, as it is not a widely recognized or documented term in the English language. The term seems to be a combination of the prefix "under-" which typically denotes something of lesser rank or status, and the word "brigadier", which is a military rank. Therefore, it can be assumed that "underbrigadier" refers to a lower-ranking officer or a subordinate to a brigadier. However, it is important to note that this term is not commonly used, and its usage and origin might vary depending on the specific context or domain.