Dimsav\Translatable\Translatable::getRelationKey PHP Method

    public function getRelationKey()
    {
        if ($this->translationForeignKey) {
            $key = $this->translationForeignKey;
        } elseif ($this->primaryKey !== 'id') {
            $key = $this->primaryKey;
        } else {
            $key = $this->getForeignKey();
        }
        return $key;
    }