The Sword of the Spirit is the Word of God. It should be drawn always, wielded by speaking it continually; in all times and seasons.
One of the benefits of praying in other tongues is that we speak mysteries, we pray things we know nothing about, the Holy Spirit prays them through us. Sometimes He provides the interpretations of our tongues and helps our understanding  but even when that doesn’t happen, we’re confident that we pray aright.