72431
I am trying to learn the readings for various words that include 月, and am
having a hard time remembering when to use がつ or げつ for the on'yomi readings.

The month names, 一月、二月、etc all use がつ, as far as I can tell. 何月 uses がつ, but
毎月 uses the げつ reading. Is there a pattern or principle governing which
reading is used, or is this a matter of rote memory?
CC BY-SA 4.0
2019-10-11T17:08:55.453
72428
2019-10-12T01:36:13.287
29490
question
readings
when to use がつ or げつ readings for 月？
When referring to a particular month, (January, February and so on) it reads
**がつ** as you mentioned:

> 一月【いちがつ】 January  
>  二月【にがつ】 February  
>  三月【さんがつ】 March  
>  四月【しがつ】 April  
>  五月【ごがつ】 May  
>  六月【ろくがつ】 June  
>  七月【しちがつ】 July  
>  八月【はちがつ】 August  
>  九月【くがつ】 September  
>  十月【じゅうがつ】 October  
>  十一月【じゅういちがつ】 November  
>  十二月【じゅうにがつ】 December  
>  何月【なんがつ】 What month  
>

However, when counting periods of time that span months, it is read **げつ** :

> 一ヶ【いっか】月【げつ】 One month  
>  二ヶ【にか】月【げつ】 Two months  
>  三ヶ【さんか】月【げつ】 Three months  
>  四ヶ【よんか】月【げつ】 Four months  
>  五ヶ【ごか】月【げつ】 Five months  
>  六ヶ【ろっか】月【げつ】 Six months  
>  七ヶ【ななか】月【げつ】 Seven months  
>  八ヶ【はっか】月【げつ】 Eight months  
>  九ヶ【きゅうか】月【げつ】 Nine months  
>  十ヶ【じゅっか】月【げつ】 Ten months  
>  十一ヶ【じゅういっか】月【げつ】 Eleven months  
>  十二ヶ【じゅうにか】月【げつ】 Twelve months  
>  何ヶ【なんか】月【げつ】 How many months  
>

Note that the small 「ヶ」 is read 「か」.

For the rest of words that use 月, I don't know if there's a rule. In general,
I just memorise the reading for each word outright.
CC BY-SA 4.0
2019-10-11T20:33:02.043
72431
2019-10-12T01:36:13.287
2019-10-12T01:36:13.287
7810
32952
72428
answer