Recently, I've been doing Japanese language processing. As far as I know,
Japanese is a tone language and there is only one accent nucleus in an accent
phrase in most cases. So, basically, there are two major tasks. One is to
combine single words into accent phrases. The other is to determine the accent
nucleus of accent phrases based on rules proposed in
[日本語単語連鎖のアクセント規則](https://www.gavo.t.u-tokyo.ac.jp/%7Emine/japanese/acoustics/sagisaka.pdf).

But the first task is very difficult to me. I've done some research but never
found any clear and comprehensive rules for that. There are some rules used in
[Open
JTalk](https://github.com/r9y9/open_jtalk/blob/1.11/src/njd_set_accent_phrase/njd_set_accent_phrase_rule_utf_8.h)
but they are too general to be accurate enough.
[OJAD](https://www.gavo.t.u-tokyo.ac.jp/%7Emine/japanese/acoustics/OJAD_Kashiwa_White.pdf)
doesn't provide any clear rules, either.

Below is a rule from OpenJTalk and an example where it's applied.

```

    「動詞」の後に「形容詞」or「名詞」がきたら別のアクセント句に
    
```

Suppose the input text is 優しい人. First, we can tokenize it into words using
MeCab.

```

    優しい 形容詞,自立,*,*,形容詞・イ段,基本形,優しい,ヤサシイ,ヤサシイ,0/4,*
    人   名詞,一般,*,*,*,*,人,ヒト,ヒト,0/2,C3
    
```

Since 優しい is 形容詞 and 人 is 名詞, using the rule above, they fall into different
accent phrases.

```

    優しい#人
    
```

Another rule is shown below.

```

    「助詞」or「助動詞」（付属語）は前にくっつける
    
```

Suppose the input text is 優しい人ですね.

```

    優しい 形容詞,自立,*,*,形容詞・イ段,基本形,優しい,ヤサシイ,ヤサシイ,0/4,*
    人   名詞,一般,*,*,*,*,人,ヒト,ヒト,0/2,C3
    です  助動詞,*,*,*,特殊・デス,基本形,です,デス,デス’,1/2,名詞%F2@1/動詞%F1/形容詞%F2@0
    ね   助詞,終助詞,*,*,*,*,ね,ネ,ネ,1/1,動詞%F1/名詞%F1/形容詞%F1
    
```

Since です and ね are 助動詞 and 助詞, respectively, they are chained to 人. Still, we
get two accent phrases.

```

    優しい#人ですね
    
```
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2023-08-23T03:32:07.263
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2023-08-23T08:22:13.817
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question
phrases pitch-accent
Are there any rules for determining accent phrases?