Though communication is one of the bedrocks of a good relationship, not all "words" are spoken. Love doesn't need audible words to express itself. The "acts of love" literally shout its message without a single syllable being uttered. John doesn't mean to say that words don't have their place, but the expression "I love you" is rather meaningless if it's just words. A lot of people hear the word "love" and wonder if the person using it has any clue what it really means.
The Bible says, "God is Love..." 1 John 4:8. And if anyone knows the meaning of love, God does! And if anyone knows how to express love, God knows! And what is the most familiar "deed" God did to show His love? John 3:16, He loved - He gave. His love was not just words spoken without meaning. His love was deeds done with infinite meaning! His deeds spoke. Love spoke.
People "hear" your love for them by "listening" to your works. What you verbally say is only as good as what your actions do. When works are absent, so is the love.