Why is う used after "o sound"?

[JayJay]

like in the words Sumo すもう, Horyuji ほうりゅうじ, and No のう to just name a few
Im still very new to Japanese and dont know everything ;;

[Schattenjedi]

It makes the お sound longer.

[JayJay]

i see..ok ありがとう

[Hiroyuki kun]

JayJay wrote:
like in the words ... Horyuji ほうりゅうじ, and No のう to just name a few...

Ok, you must keep in mind that 'romaji' is only approximations of the japanese phonetic sounds. There are three sytems to write japanese in roman letter which is the Hepburn, Nipponshiki and the Kunreishiki system. The most popular is the Hepburn system.

The 'u' (う) is usually slightly silent in pronunciation after a consonant but it is written in kana. It's usually the same with 'i' (い). So the word 'Horyuji' is written the way it is pronounced in Japanese because the 'u' which occurs in the kana writing is silent. If 'u' follows another vowel. It lengthens the sound of the preceding vowel such as in のう.

I hope this makes sense.