In Finnish, the optative or the second imperative, is archaic, mainly appearing in poetry, and used in suppletion with the first imperative. It is formed using the suffixes -"ko-" and -"kö-", depending on vowel harmony, whereas the first imperative uses the suffixes -"ka-" and -"kä-", both cases subjected to consonant gradation; for instance, "kävellös" (thou shalt walk) is the active voice second person singular in present optative of the verb "kävellä" (to walk), and "ällös kävele" is the negative (don’t walk). (The corresponding first imperative forms are "kävele" and "älä kävele".)