It is indeed not the place to post this...
One should have contacted the TT coordinator for Afrikaans
https://community.joomla.org/translations/joomla-3-translations.html#af-za

But it seems you found a bug
The lower and upper limits are defined by the TT in the xx-XX.localise.php
which gives for Afrikaans and en-GB

/**
	 * Returns the lower length limit of search words
	 *
	 * @return	integer  The lower length limit of search words.
	 * @since	1.6
	 */
	public static function getLowerLimitSearchWord() {
		return 3;
	}
	/**
	 * Returns the upper length limit of search words
	 *
	 * @return	integer  The upper length limit of search words.
	 * @since	1.6
	 */
	public static function getUpperLimitSearchWord() {
		return 20;
	}
	/**
	 * Returns the number of chars to display when searching
	 *
	 * @return	integer  The number of chars to display when searching.
	 * @since	1.6
	 */
	public static function getSearchDisplayedCharactersNumber() {
		return 200;
	}

COM_SEARCH_ERROR_SEARCH_MESSAGE="Search term must be a minimum of %1$s characters and a maximum of %2$s characters."

Therefore the error is created by this code

if (SearchHelper::limitSearchWord($searchWord))
		{
			$error = JText::sprintf('COM_SEARCH_ERROR_SEARCH_MESSAGE', $lower_limit, $upper_limit);
		}

The Afrikkans string is not following the en-GB value
COM_SEARCH_ERROR_SEARCH_MESSAGE="Soektog term moet 'n minimum van 3 karakters en 'n maksimum van 20 karakters hê."

But he tried to reflect what should be (forget the hê for now);

we should have indeed
`Search term must be a minimum of 3 characters and a maximum of 20 characters.

I guess the error is here:
https://github.com/joomla/joomla-cms/blob/staging/libraries/joomla/language/language.php#L590-L598

By curiosity I looked at 1.6.0 and I found that we had there the right code

/**
	 * getUpperLimitSearchWord function
	 *
	 * This method returns an upper limit integer for length of search words
	 *
	 * @return	integer	The upper limit integer for length of search words (20 if no value was set for a specific language)
	 * @since	1.6
	 */
	public function getUpperLimitSearchWord() {
		if ($this->upperLimitSearchWordCallback !== null) {
			return call_user_func($this->upperLimitSearchWordCallback);
		}
		else {
			return 20;
		}
	}

hhm
#5103
#5121

confused...

Basically this means that the upperlimit setting is always overriden if <200
weird

@infograf768 did you forget about this?

After thought: #5121 was correct. Only the Afrikkans string is incorrect.
For 4.0, we should change the default upperlimit to 200 in en-GB.localise.php and let this know to TTs