- [4ヶ月前]{よん・か・げつ・まえ}から ⇔ From 4 months ago
- [4月]{し・がつ}から ⇔ From April
- [4日前]{よっかまえ}から ⇔ From 4 days ago
- [今月4日]{こんげつよっか}から ⇔ From the 4th of this month
Time interval for months is indicated by adding the character "ヶ” (pronounced ka) before 月.
The small ke (ヶ) is a Japanese character, typographically a small form of the katakana character ケ ke. While identical in shape to a small ケ, the shape is actually an abbreviation for the kanji 箇 [more at
Wikipedia, Small ke
]
Etymology: 箇/個/个 is a counter used sometimes in Chinese coming before the object, but in Japanese is only used before the object for counting months, and in other cases where it is used, it always comes after, e.g.,
- Japanese [4ヶ月]{よん・か・げつ}, c.f. 4个月 (Simplified Ch.), 4個月 (Traditional Ch.)
- unique instance where Japanese borrows Chinese pre position 個 counter regular expression:
- {number}{counter(noun)}{noun}
- Japanese [一人]{ひとり}, c.f. 一個人 (Traditional Ch.) or 一个人 (Simplified Ch.) -
- unique case (including [一人前]{いち・にん・まえ}) of native Japanese post position counter regular expression:
- {number}{counter(noun)}
- Japanese [一日間]{いち・にち・かん}, c.f. 一天 (Traditional+Simplified Ch. - no counter!)
- usual case of native Japanese post position counter regular expression:
- {noun}{number}{counter(noun)}
Note: I don't have a reference to show that the first two cases above described as "unique" are actually unique. If someone knows a reference or a counter example, please post.