Jessie can always use volunteers for both the health clinic and teaching English.
Volunteering for the health clinic usually includes such tasks as helping to fill vials with homeopathic medicines or writing down the names of people who visit the clinic. Health clinics are held at Gyanjyoti Ashram and also in surrounding villages.
English instruction is done at small local schools. Volunteering as an English teacher requires no formal training, but previous experience is helpful. The age of students vary from about five up to around thirteen with the average being somewhere in between. Instruction can vary from basic lettering (a, b, c, d), to simple sentences ("Where are you from?", "How old are you?"). The local children enjoy learning English and work hard during classes. Although you are teaching some of the very poorest India, you'll will probably be surprised at how enthusiastic the kids are and how fast they learn.
School materials in rural Bihar are very basic - lessons are often given on a handheld chalkboard and the class may be held in a community building which requires a sweeping before class begins. Bringing teaching props with you from your home country would be very helpful.