This paper classifies distinctive phenomena occurring in Japanese spontaneous speech, and proposes a grammar and processing techniques for handling them. Parsers using a grammar for written sentences cannot deal with spontaneous speech because in spontaneous speech there are phenomena that do not occur in written sentences. A grammar based on analysis of transcripts of dialogues was therefore developed. It has two distinctive features: it uses short units as input units instead of using sentences in grammars for written sentences, and it covers utterances including phrases peculiar to spontaneous speech. Since the grammar is an augmentation of a grammar for written sentences, it can also be used to analyze complex utterances. Incorporating the grammar into the distributed natural language processing model described elsewhere enables the handling of utterances including variety of phenomena peculiar to spontaneous speech.