How to determine which language to display to each visitor?
We must consider two cases: visitors who arrive on our website for the first time and those returning. For a user arriving on your website for the first time, your website must make his best guess on which language to display. There are two main ways: get the information from your visitor's web browser, or identify from its IP address.
Determine your visitor's default language from the information shared by his web browser
Use your visitor's IP address to know his location and deduct his favorite language
The fastest and cheapest way is to call a real-time IP Geolocation API with the visitor's IP address. The API will match the IP address with the corresponding country, and then you can deduce the language. The quality of detection depends on the precision of the API you will be calling. Abstract provides an accurate IP geolocation service, accessible for free. You only need to create an account, no credit card required, to obtain your API key.
Don't forget to allow your visitor to select your website language manually
You must provide your users with a system that allows them to manually change the language, such as a list of flags or language names placed in the header of your pages. Note that various flag images, including emojis, are available in Abstract's IP Geolocation API. There are other IP Geolocation API's that you can use for this as well. Once a visitor makes his selection, your website must refresh the current page in the targeted language and memorize it using a cookie. When he returns to your website, the language previously selected will be automatically used for display. Another useful feature is to incorporate a website screenshot API to easily show users how your website looks in either language, which could be further improved with the help of an image optimizing API.