PhpSpreadsheet/docs/topics/settings.md

Configuration Settings

Once you have included the PhpSpreadsheet files in your script, but before instantiating a Spreadsheet object or loading a workbook file, there are a number of configuration options that can be set which will affect the subsequent behaviour of the script.

Cell collection caching

By default, PhpSpreadsheet holds all cell objects in memory, but you can specify alternatives to reduce memory consumption at the cost of speed. Read more about memory saving.

To enable cell caching, you must provide your own implementation of cache like so:

$cache = new MyCustomPsr16Implementation();

\PhpOffice\PhpSpreadsheet\Settings::setCache($cache);

Language/Locale

Some localisation elements have been included in PhpSpreadsheet. You can set a locale by changing the settings. To set the locale to Brazilian Portuguese you would use:

$locale = 'pt_br';
$validLocale = \PhpOffice\PhpSpreadsheet\Settings::setLocale($locale);
if (!$validLocale) {
    echo 'Unable to set locale to ' . $locale . " - reverting to en_us" . PHP_EOL;
}

• If Brazilian Portuguese language files aren't available, then Portuguese will be enabled instead
• If Portuguese language files aren't available, then the setLocale() method will return an error, and American English (en_us) settings will be used throughout.

More details of the features available once a locale has been set, including a list of the languages and locales currently supported, can be found in Locale Settings for Formulae.