Semitone
a high pitch
A pitch indicator is called a metronome tuner.
Two notes that sound the same in pitch but have different names are 'enharmonically equivalent'. E.g. F# and Gb sound the same but they are written differently.
All drums can change pitch, but you're most likely thinking of Timpani, or Kettle Drums.
The harder you pluck the strings, the louder they get. You can change the pitch by using thick or thin strings
Inflection
Ummm . . . the change of pitch is called a modulation. Perhaps that is what you are asking. Or . . . a higher-pitched harmony in singing is called a Descant.
Do you mean "The Doppler Effect"?
Elevators change the pitch of the aircraft.
The apparent change in pitch of a moving sound source is called the Doppler effect. It describes how the frequency of the sound waves perceived by an observer changes as the source of the waves moves relative to the observer.
change (evolution, modification) is spelled "change" in French. change (small coins) is called "la monnaie"
Tremolo is a rapid quivering change of volume. This is not to be confused with a small, rapid changes in pitch, which is known as vibrato.
Valves. They're used to change the pitch.
As the frequency of a sound wave changes, the pitch of the sound will also change. Higher frequencies will result in higher-pitched sounds, while lower frequencies will produce lower-pitched sounds. This change in pitch is a result of the number of wave cycles per second altering the perception of the sound's frequency.
It is called "pitch."
That is called "acceleration". In symbols, that would be a = dv/dt; this means change in velocity divided by change in time, for a small time period.
The frequency of the sound wave must change in order to change the pitch of a sound. A higher frequency results in a higher pitch, while a lower frequency results in a lower pitch.