public function stem($token, $lang)
	{
		// Check if the token is long enough to merit stemming.
		if (\strlen($token) <= 2)
		{
			return $token;
		}

		// Check if the language is English or All.
		if ($lang !== 'en')
		{
			return $token;
		}

		// Stem the token if it is not in the cache.
		if (!isset($this->cache[$lang][$token]))
		{
			// Stem the token.
			$result = $token;
			$result = self::step1ab($result);
			$result = self::step1c($result);
			$result = self::step2($result);
			$result = self::step3($result);
			$result = self::step4($result);
			$result = self::step5($result);

			// Add the token to the cache.
			$this->cache[$lang][$token] = $result;
		}

		return $this->cache[$lang][$token];
	}