private function getDictionaryFolder(): string
    {
        if (null === $this->bundledDictFolder) {
            $binary = $this->getBinary();
            if (realpath($binary) === false) {
                $process = new Process(['which ' . $this->getBinary()]);
                $process->run();
                if (!$process->isSuccessful()) {
                    throw new EnvironmentException(
                        sprintf('Can not find full path of ispell: %s', $process->getErrorOutput())
                    );
                }
                $binary = trim($process->getOutput());
            }
            $this->bundledDictFolder = dirname($binary, 2) . '/lib/ispell';
        }

        return $this->bundledDictFolder;
    }