う・よう形 ・ Volitional Form
In Japanese you can express the idea of “lets do” or “shall we do” something by using the volitional form verb conjugation. Godan (Group I) verbs and ichidan (Group II) verbs both have their own conjugation rules.
ごだん動詞 Godan Verbs
Start with a plain form verb (ふつう形), remove the [u] ending sound and replace it with the [o] ending sound hiragana, and then add う. All plain form verbs end in the [u] column on the hiragana chart, so you can just move down two rows to find the corresponding [o] ending sound. You can also start in the polite/masu form (ます形) by cutting off the ます and changing the [i] ending sound hiragana to the [o] ending sound hiragana.
- (I) buy → Let's/shall we buy買う → 買おう
- (I) drink → Let's/shall we drink飲む → 飲もう
- (I) return → Let's/shall we return (home)帰る → 帰ろう
いちだん動詞 Ichidan Verbs
For this verb group you should start by finding the verb root, or verb stem. You can find the verb root by first starting in the polite/masu form (ます形 ). The verb stem is just the polite/masu form (ます形 ) without the ます. Once you’ve found the verb root all you need to do is add よう.
- (I) see/watch → Let's/shall we see/watch見る → 見よう
- (I) eat → Let's/shall we eat食べる → 食べよう
- (I) walk → Let's/shall we walk起きる → 起きよう
Irregular verbs are just that — irregular. They don’t have any set rules. Fortunately there aren’t a whole lot of them. The most common are する・to do, and 来る・to come.
- (I) do → Let's/shall we doする・します → しょう・しましょう
- (I) come → Let's/shall we come来(く)る・来（き）ます → 来（こ）よう
If you see a mistake please correct me! You can leave your correction in the comments below. I am not a native speaker. I just have a love of the language and enjoy studying it. I made these study materials in order to help my learning process. I am posting them online in hopes that it can help others too. Let’s learn Japanese together! 🙂