I am going to do a project in which the user moves his head in order to control the cursor across the computer screen using accelerometer sensor and gyroscope sensor (not combined). And for the mouse click, I've chosen the voice recognition.
Is the Raspberry Pi suited for my project?
From the given project description I'll jump for: Yes, it seems reasonable that a RaspberryPi can handle this project. Accelerometers and gyroscopes can be connected via the GPIO pins and the computational power is certainly sufficient to process speech - especially for something as limited as in this task "click". Instead of repeating content here I'll give just a meta-answer and some links that deepen the matter significantly.
Accelerometer/Gyro
A variety of accelerometers and gyros are available. Since those use different interfaces (e.g. SPI or I2C) it's of little use to point to specific previous answers. It's advisable to pick the sensors and then check back with their respective specifications and more detailed questions how to interface them.
Voice recognition
The RPi jasper project @ https://jasperproject.github.io/ might be of interest to you. Also you might take a look at Project Oxford @ https://www.projectoxford.ai/speech to leverage their engine.
