Correct spelling for the English word "mixest" is [mˈɪksəst], [mˈɪksəst], [m_ˈɪ_k_s_ə_s_t] (IPA phonetic alphabet).
The word "mixest" is the second-person singular present form of the verb "mix" in Early Modern English, which is an earlier stage of the English language that was used from the late 15th century to the mid-17th century.
The root of "mix" can be traced back to the Latin word "miscere", which means "to mix" or "to mingle". In Old English, the word "miscian" was used, which eventually evolved into "mix" in Middle English.
The "-est" ending in "mixest" is the second-person singular present indicative ending in Early Modern English. In this form, the verb "mix" is conjugated for the subject "you" in the present tense.
It's worth noting that "mixest" is no longer in common usage, as Early Modern English has evolved into Modern English over time.