A diptote is a noun that reflects the nominative case with the ضمة vowel, and both accusative and genitive cases with the فتحة vowel. Moreover, such a noun does not receive تنوين التمكن (a type of nunation). In Arabic, a diptote is noun as ممنوع من الصرف or غير منصرف (change restricted).
In the examples below, note that certain words are in the genitive case yet they reflect this case with a فتحة. Note also that they do not retain nunation despite expectation of the contrary.
in many mosques
في مساجدَ كثيرةٍ
the faith of Abraham
Under What Circumstances Do Diptotes Become Change Restricted?
Diptotes are not always change restricted; there are cases where the last letter receives a كسرة in order to reflect the genitive state. Those cases are as follows.
· when the noun is مضاف
· when the noun is prefixed with ال
In the examples below, there are diptotes but they are not change restricted due to falling into one of the above mentioned categories.
in the predefined mosques
في المساجدِ المعهودةِ
the faith of Abraham of Mecca
إيمان إبراهيمِ مكةَ
Which Nouns are Diptotes
The following categories of nouns are diptotes.
1. names or adjectives with a deviated construction
For example, the word اُخَر is an adjective and its construction is deviated. Its construction is deviated because this word is the plural for the feminine comparative word آخر. Grammar dictates that when comparative nouns are used without ال and they are not مضاف that the singular masculine versions be used despite the context. Yet the feminine plural أخر is used without ال and not as مضاف. This usage is a deviation from the rules of grammar and so the word, coupled with its being an adjective, is change restricted.
2. feminine names
For example, the word زينب is a name and it is feminine.
3. words feminine by means of an الف مقصورة or an الف ممدودة
For instance, the word أشياء ends in an الف ممدودة and the word كمثرى ends in an الف مقصورة. However, the word عصا, although it ends in an الف مقصورة, the الف is not for femininity, and thus عصا is not a diptote.
4. foreign names
The Hebrew names ابراهيم, إسحاق, يعقوب, إسماعيل are all diptotes.
5. nouns pluralized using a منتهى الجموع pattern
There are three منتهى الجموع patterns in the language. These are patterns that signify plurals that have been pluralized to the highest degree and can be pluralized no further. Actually, these are not patterns, rather three groups of patterns. Below is a hierarchy of these three pattern-groups; each group contains some sample patterns, and each pattern contains some sample words.
· a plural with an الف of plurality near the end, followed by a مكسور letter, followed by the final letter
· same as above, except the final two letters after the الف of plurality have geminated
· a plural with an الف of plurality near the end, followed by a مكسور letter, followed by a long vowel ـي, followed by the final letter
6. hyphenated names
For example, بعلبك is a name created by hyphenating the proper nouns بعل and بك.
7. names or adjectives with an extra ـان at the end
For instance, the word سكران is an adjective meaning ‘drunk’ and its base letters are س، ك، ر. Thus the ان at the end is extra and so the word is thus a diptote.
8. names or adjectives on the pattern of a verb
The word احمد is both a name and it is on the pattern of the first-person, active imperfect verb.