WPML: string registration & translation

For free-form / dynamic strings your plugin emits that WPML can't reach otherwise — option values entered in your settings, admin-defined labels, messages built at runtime. Static UI text stays on normal WordPress i18n (__(), _e() + .po/.mo); this skill is only for strings that live in the database or are generated dynamically.

Read this first — it needs the String Translation add-on

The base plugin only FIRES the string hooks; the handlers that actually store and translate strings ship with the separate WPML String Translation add-on. Verified: there is no add_action('wpml_register_single_string', …) or add_filter('wpml_translate_single_string', …) anywhere in sitepress-multilingual-cms, and icl_register_string / icl_t / icl_gettext are not defined in the base plugin.

Standard WordPress hook semantics then give you a safe default only for the hook form:

• apply_filters('wpml_translate_single_string', $value, …) with no handler → returns $value unchanged (original text; safe fallback).
• do_action('wpml_register_single_string', …) with no handler → silent no-op.
• icl_register_string() / icl_t() called directly with ST inactive → fatal undefined function unless guarded.

So: prefer the hook form (degrades safely), and if you use the legacy icl_* functions, guard every call with function_exists().

Detecting String Translation