In linguistics, intonation is the variation of pitch when speaking. Intonation and stress are two main elements of linguistic prosody. Many languages use pitch syntactically, for instance to convey surprise and irony or to change a statement to a question. Such languages are called intonation languages. English and French are well-known examples. Some languages use pitch to distinguish words; these are known as tonal languages. Thai and Hausa are examples. An intermediate position is occupied by languages with tonal word accent, for instance Norwegian or Japanese. Rising intonation means the pitch of the voice increases over time; falling intonation means that the pitch decreases with time. A dipping intonation falls and then rises, whereas a peaking intonation rises and then falls. The classic example of intonation is the question-statement distinction. For example, northeastern American English, like very many languages (Hirst & DiCristo, eds. 1998), has a rising intonation for echo or declarative questions (He found it on the street?), and a falling intonation for wh- questions (Where did he find it?) and statements (He found it on the street.). Yes or no questions (Did he find it on the street?) often have a rising end, but not always. The Chickasaw language has the opposite pattern, rising for statements and falling with questions.