There are several plugins which convert your WordPress blog to multilingual sites including Polylang, qTranslate X and WPML. Polylang and qTranslate X are free and will be suitable for personal blogs.
WPML is a premium Multilingual plugin. Many themes such as AVADA, Enfold, BeTheme, X, Jupiter and Bridge indicate that they are compatible with WPML. WPML are available in three versions: Multilingual Blog, Multilingual CMS and Multilingual CMS Lifetime.
Multilingual Blog is for blog users. It’s desirable that companies use WPML rather than Polylang or qTranslate. Free plugins might slow down your site. (Actually, I uninstalled Polylang due to this reason.) However, I found that WPML does not slow down my WordPress site.
Some users install a Google Translate (Machine Translation) plugin on their blogs. But machine translation makes a negative on search engine optimization (SEO) since it does not create unique URLs for translated pages. Currently I use WPML on this blog and I think it will be a good option for those who run multilingual versions on their WordPress blogs.
WPML is fully localized and lets you easily build and run multilingual e-commerce sites with WooCommerce (using WooCommerce Multilingual).