The Japanese parser supports Subject – Object – Verb (SOV) sentences. The subject or object part may contain additional verbs. Such verbs are ignored since the ending verb is the active verb for the sentence.
Japanese verbs conjugate for politeness level, tense, aspect, voice and sense:
In Oracle Policy Modeling, the verbs list contains entries for the following combinations:
Level |
Tense |
Aspect |
Voice |
Sense |
---|---|---|---|---|
Polite |
Present, past |
Perfect |
Active, passive |
Positive, negative |
Polite |
Present, past |
Progressive |
Active |
Positive, negative |
Polite |
Present, past |
Potential |
Active |
Positive, negative |
Plain |
Present, past |
Perfect |
Active, passive |
Positive, negative |
Plain |
Present, past |
Progressive |
Active |
Positive, negative |
Plain |
Present, past |
Potential |
Active |
Positive, negative |
For each of the above forms, the verbs are inflected by suffixing some ending based on which verb group they belong to. The three verb groups covered by the Japanese parser are:
(All forms of Japanese verbs end in the -u sound. This form is the plain, present, active verb form.)
The verbs do not inflect for gender or person.
The copula だ (da) which is the infinitive form of です (desu), and である (dearu) which is the infinitive form of であります, have been included in the verbs list.
For compound verbs where only the second verb is inflected, eg benkyo + suru, suru is taken to be the active verb. For such noun + suru verbs, there is no need to enter the compound verbs separately as long as suru is in the verbs list.
The automatic verb conjugations works for the majority of the ichidan and godan verbs. The conjugations for irregular verbs, and verbs where the use of kanji character introduces ambiguity as to whether the verb is ichidan or godan, will have to be entered manually. See Configure list of recognized verbs for more information.
In an SOV sentence, the verb at the end is taken to be the active verb. If adjectives are present within the sentence, they are not inflected.
In a verbless sentence, the adjectives may be inflected. There are two form of Japanese adjectives, the -na adjectives and the -i adjectives.
In both the above scenarios and also for an SOV sentence, when the uncertain form is constructed the copula is omitted.
The parser only supports a limited number of counter words such as those for age, number of people etc.
The following verb inflections are currently not handled.
The first three forms are unlikely to occur in the OPA rulebase framework.
For the fourth and fifth verb forms, OPA has an existing framework for expressing conditionals and clausal relationships when developing a rulebase. As such, these verb inflections are redundant. For the sixth form, expressing 'must', the sentence should be rephrased, for example using the verb 'obligated'.
For example, look at the following sentences.
The person is eligible if the person pays tax.
当人は税金を払ったら、適格である。
In Oracle Policy Modeling this should be written as two separate sentences where the first one is formatted as the conclusion and the second one as the level 1 condition.
The person is eligible.
当人は適格である。
The person pays tax.
当人は税金を払います。
The person is retired and the person’s age is greater than 65.
当人は退職していて、(年齢が)65歳以上である。
The above sentence should be broken down into two separate discrete sentences.
The person is retired and
当人は退職している。および
The person’s age is greater than 65
当人は(年齢が)65歳以上である。
Here the sentences represent two conditions that need to occur simultaneously. This will be reflected by the 'and' rather than inflecting the verb to the -te form. Thus, if there are sentences where verb forms that are not covered by the verb editor are used, you should try to rewrite them as separate attributes especially when the sentences are clausal in nature.
For expressing necessity, sentences should be rephrased to use a noun + copula form. Another way is to simply rephrase the sentences. For example,
'A person must have a pension card changes' to
'A person owns a pension card'.