Bells reverberate joyous sound which always signify celebration. After the bells ring during the Gloria of the “Mass of the Last Supper” on Holy Thursday, a wooden clapper is used from then on 'til Easter Vigil. The profound silence of the bells gives way to the rhythmic strikes of the wooden clapper which make the mood somber as the faithful begins to contemplate on the Passion of Our Lord Jesus Christ.
The Latin term for this Lenten wooden clapper is “Crotalus” which originated from the Greek word “krotalon” (κροταλον) which means "rattle". It manages to get the attention of the faithful and invite them to solemn prayer as the Blessed Sacrament is carried to the Altar of Repose. It may also be used during Good Friday processions.
In the Philippines, some call it "takatok" while others "takatak". We sometimes describe something on how it sounds like "kling-kling" for the altar bells to supplement what's lacking in the vocabulary. Our friend "Chiness", a follower of our blog, gave a good addendum below:
"Tagalogs normally call these "matraka" from the Spanish "matraca," the more correct way of referring to the contraption in the language. "Crótalos" in Spanish mean cymbals; in Filipino, "pompyang."
Our parish in Southern Leyte used to have a huge set of clappers set atop the belfry and operated by gears at the base. These were clapped during the Triduum sacrum. We called these "tinieblas" from the the Spanish "officio de tinieblas," from the Latin "officium tenebrae," which consist of the hours of matins and lauds in the Triduum."