We distinguish between subjective, introspective methods of phonetic investigation and objective methods.
The oldest, simplest and most readily available method is the method of direct observation. This method consists in observing the movements and positions of one's own or other people's organs of speech in pronouncing various speech sounds, as well as in analyzing one's own kinaesthetic sensations during the articulation of speech sound in comparing them with auditory impressions.
Objective methods involve the use of various instrumental techniques (palatography, laryngoscopy, photography, cinematography, X-ray photography and cinematography and electromyography). This type of investigation together with direct observation is widely used in experimental phonetics. The objective methods and the subjective ones are complementary and not opposite to one another. Nowadays we may use the up-to-date complex set to fix the articulatory parameters of speech - so called articulograph.
Acoustic phonetics comes close to studying physics and the tools used in this field enable the investigator to measure and analyze the movement of the air in the terms of acoustics. This generally means introducing a microphone into the speech chain, converting the air movement into corresponding electrical activity and analyzing (Ксень, это слово у Красы через «s», но, по-моему, тут «z») the result in terms of frequency of vibration and the amplitude of vibration in relation to time. The spectra of speech sounds are investigated by means of the apparatus called the sound spectrograph. Pitch as a component of intonation can be investigated by intonograph.
The acoustic aspect of speech sounds is investigated not only with the help of sound-analyzing techniques, but also by means of speech-synthesizing devices.