protected function processWeakWord ($word) {
		$index = 0;
		$text = ' ' . $this->text . ' ';
		// go through infinite loop and process given week word with html fixed spaces replacement
		while (TRUE) {
			$index = mb_strpos($text, ' ' . $word . ' ');
			if ($index !== FALSE) {
				// If there is any week word and basic white space
				// before and after the week word in source text:
				//	- take all source text before week word including white space before week word,
				//	- take week word
				//	- add fixed space html entity
				//	- and add all rest source text after week word
				//	  and white space char after week word
				$text = mb_substr($text, 0, $index + 1) . $word . '&nbsp;' . mb_substr($text, $index + 1 + mb_strlen($word) + 1);
				// move $index variable after position, where is source text already processed
				$index += 1 + mb_strlen($word) + 6; // (6 - means length of space html entity: '&nbsp;'
			} else {
				// there is no other occurrence of week word in source text
				break;
			}
		}
		$this->text = mb_substr($text, 1, mb_strlen($text) - 2);
	}