As the numbers show, by only having your content in one language, you’re missing a huge amount of people. For example, if you work for a business that is only tweeting in English but are also targeting consumers in Spain, you’re unlikely to reach those people without Spanish-language interaction.
Translation and localization is used to reach that targeted audience. So make sure to research what markets would be beneficial for you to target, look at what materials or content would best bring in those people, and then translate and localize your materials to ultimately reach those markets.
Also, make sure you have a trusted translation partner who can provide high-quality services, because this an area where mistakes can be costly by financially and reputation-wise.