vBulletin Manual - Using Phrases in Templates

Phrases are generally straightforward to use in templates. Simple phrases (without any variable portions) can be referenced like regular $variables; complex phrases are referenced similarly to template conditionals.

When referencing a phrase in a template, there are two things you have to know.

The variable name (varname) – this is what uniquely identifies a phrase and how phrases are referenced. Generally, the variable name reflects the phrase text directly; for example, the phrase with variable name poll_timeout has the text of Poll Timeout.
The phrase group – if the phrase is in a group, you will only be able to access it on pages that load that group. For example, the Polls group is only loaded in poll.php, so if you try to reference poll_timeout in a template that’s loaded on another page, you won’t get any output.

Note:

Some of the following is fairly complex and technical. If you do not wish to add phrases to your templates, then this section does not apply to you.

To reference a simple phrase, you need to place $vbphrase[variable_name] into the appropriate template, replacing variable_name with the appropriate variable name.

If the phrase contains variable portions ({1}, {2}, etc), then you will need to use the <phrase> tag. The general syntax for the <phrase> tag is:

<phrase argument_list>$vbphrase[variable_name]</phrase>

variable_name represents the variable name of the phrase; this part is the same as with simple phrases.
argument_list represents a list of variables or text that are used to populate variable sections of the phrase. Each argument is in the form of #="value", where # starts at 1 and increases.

For example, the FORUMDISPLAY template contains:

<phrase 1="$limitlower" 2="$limitupper" 3="$totalthreads">$vbphrase[showing_threads_x_to_y_of_z]</phrase>

This will populate showing_threads_x_to_y_of_z with the values of $limitlower ({1}), $limitupper ({2}), and $totalthreads ({3}) similar to the showing_avatars_x_to_y_of_z example in the Phrase Syntax section.