WordPress at a glance
filter is not described

ngettext filter-hook . WP 2.2.0

Filters the singular or plural form of a string.

Usage

add_filter( 'ngettext', 'filter_function_name_4355', 10, 5 );
function filter_function_name_4355( $translation, $single, $plural, $number, $domain ){
	// filter...

	return $translation;
}
$translation(string)
Translated text.
$single(string)
The text to be used if the number is singular.
$plural(string)
The text to be used if the number is plural.
$number(string)
The number to compare against to use either the singular or plural form.
$domain(string)
Text domain. Unique identifier for retrieving translated strings.

Where the hook is called

_n()
wp-includes/l10n.php 425
return apply_filters( 'ngettext', $translation, $single, $plural, $number, $domain );

Where the hook is used (in WP core)

Does not used.