1. Download and install http://www.poedit.net/download.php
2. Go to /wp-content/themes/visage/languages/ and open en_EN.po file.
3. In the window that appears you have all the strings that were used in this theme, so you just need to go through them and write a translation.
4. When you’re done go to File > Save as and save your translation in a *.po file.
You should name your file pt_LANG. It’s just a naming convension WordPress_in_Your_Language.
5. When you’re done translating open wp-config.php from your WordPress root folder and replace this line: define (‘WPLANG’, ”); with define (‘WPLANG’, ‘pt_LANG’).
*Since WordPress 4.0 site language defines in dashboard=>settings=>general
so… I try this, but how I have WordPress 4.9.1, obviously, I configured the system with the correct lang (es_ES), but this not work, please I need your support.