Current views vary on whether all languages have a verb phrase; some schools of generative grammar (such as principles and parameters) hold that all languages have a verb phrase, while others (such as lexical functional grammar) take the view that at least some languages lack a verb phrase constituent, including those languages with a very free word order (the so-called non-configurational languages, such as Japanese, Hungarian, or Australian aboriginal languages), and some languages with a default VSO order (several Celtic and Oceanic languages).