diff --git a/resources/function_help/json/format_date b/resources/function_help/json/format_date
index 19141611636..d76da458234 100644
--- a/resources/function_help/json/format_date
+++ b/resources/function_help/json/format_date
@@ -6,7 +6,7 @@
   "arguments": [
 	{"arg":"datetime","description":"date, time or datetime value"},
 	{"arg":"format","description":"String template used to format the string. <table><thead><tr><th>Expression</th><th>Output</th></tr></thead><tr valign=\"top\"><td>d</td><td>the day as number without a leading zero (1 to 31)</td></tr><tr valign=\"top\"><td>dd</td><td>the day as number with a leading zero (01 to 31)</td></tr><tr valign=\"top\"><td>ddd</td><td>the abbreviated localized day name (e.g. 'Mon' to 'Sun')</td></tr><tr valign=\"top\"><td>dddd</td><td>the long localized day name (e.g. 'Monday' to 'Sunday')</td></tr><tr valign=\"top\"><td>M</td><td>the month as number without a leading zero (1-12)</td></tr><tr valign=\"top\"><td>MM</td><td>the month as number with a leading zero (01-12)</td></tr><tr valign=\"top\"><td>MMM</td><td>the abbreviated localized month name (e.g. 'Jan' to 'Dec')</td></tr><tr valign=\"top\"><td>MMMM</td><td>the long localized month name (e.g. 'January' to 'December')</td></tr><tr valign=\"top\"><td>yy</td><td>the year as two digit number (00-99)</td></tr><tr valign=\"top\"><td>yyyy</td><td>the year as four digit number</td></tr></table><p>These expressions may be used for the time part of the format string:</p><table><thead><tr><th>Expression</th><th>Output</th></tr></thead><tr valign=\"top\"><td>h</td><td>the hour without a leading zero (0 to 23 or 1 to 12 if AM/PM display)</td></tr><tr valign=\"top\"><td>hh</td><td>the hour with a leading zero (00 to 23 or 01 to 12 if AM/PM display)</td></tr><tr valign=\"top\"><td>H</td><td>the hour without a leading zero (0 to 23, even with AM/PM display)</td></tr><tr valign=\"top\"><td>HH</td><td>the hour with a leading zero (00 to 23, even with AM/PM display)</td></tr><tr valign=\"top\"><td>m</td><td>the minute without a leading zero (0 to 59)</td></tr><tr valign=\"top\"><td>mm</td><td>the minute with a leading zero (00 to 59)</td></tr><tr valign=\"top\"><td>s</td><td>the second without a leading zero (0 to 59)</td></tr><tr valign=\"top\"><td>ss</td><td>the second with a leading zero (00 to 59)</td></tr><tr valign=\"top\"><td>z</td><td>the milliseconds without trailing zeroes (0 to 999)</td></tr><tr valign=\"top\"><td>zzz</td><td>the milliseconds with trailing zeroes (000 to 999)</td></tr><tr valign=\"top\"><td>AP or A</td><td>interpret as an AM/PM time. <i>AP</i> must be either 'AM' or 'PM'.</td></tr><tr valign=\"top\"><td>ap or a</td><td>Interpret as an AM/PM time. <i>ap</i> must be either 'am' or 'pm'.</td></tr></table>"},
- {"arg":"language","optional":true,"description":"language (lowercase, two- or three-letter, ISO 639 language code) used to format the date into a custom string"}
+ {"arg":"language","optional":true,"description":"language (lowercase, two- or three-letter, <a href='https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes'>ISO 639 language code</a>) used to format the date into a custom string"}
   ],
   "examples": [ { "expression":"format_date('2012-05-15','dd.MM.yyyy')", "returns":"'15.05.2012'"},
                 { "expression":"format_date('2012-05-15','d MMMM yyyy','fr')", "returns":"'15 mai 2012'"}