I build a 4 languages site, i use sub domain as the home page for the other 3 languages, Es.domain.com, RU. domain.com, Fr. domain.com, and the homepage is English www.domain.com. I submit the sitemap to Google, but only 1/3 pages are indexed, that's why? Any suggestions? Should I submit the sitemap by 4 languages? Kindly regards!
If the site is new, then just focus on building more backlink point to the sub-domain. Submitting sitemap is not necessary, search engine is smart enough to find your site if you have a strong backlink
OK. thank you, now start to make more backlinks to the main domain and the sub domains hope that will help
If your sub-domain is in other languages such as fr, then it is better to get some backlink fromsite in fr languages.