5.4.2 Use of Interpreter and Writing in Confession
1. Penitents who cannot speak or understand the spoken language of the confessor may communicate by other appropriate means. These include the use of sign language between the confessor and penitent directly or even writing. 
2. Provided that any abuse, scandal or breach of the seal is avoided, penitents may use an approved sign language interpreter or language interpreter of their choice. The confessor is to remind any interpreter of the obligation to observe secrecy contained in canon 983 §2, and to destroy any written materials that a penitent provides or return them to the penitent. 
 USCCB, Guidelines for the Celebration of the Sacraments with Persons with Disabilities (rev. June 2017), nn. 29-30.