No, the speed of sound in a medium is not affected by the motion of the sound source or the listener. The speed of sound is determined by the properties of the medium through which the sound wave propagates, such as its density, elasticity, and temperature.
In a stationary situation, such as when you are standing still and speaking, the sound waves generated by your voice will propagate through the medium (such as air) at a certain speed, which is approximately 343 meters per second (or about 767 miles per hour) in dry air at sea level and at around 20 degrees Celsius.
Now, if you are moving while speaking, for example, if you are in a moving vehicle, the speed of sound waves relative to you (the source) and an observer who is also in motion with the same velocity will remain the same. This is because the motion of the source and the observer does not change the speed of sound in the medium.
However, there may be perceived changes in the pitch or frequency of the sound waves due to the Doppler effect. The Doppler effect is the change in frequency or pitch of a wave as perceived by an observer when the source of the wave and/or the observer is in relative motion. For example, if you are moving towards an observer, the sound waves will appear to have a higher frequency, leading to a higher perceived pitch. Conversely, if you are moving away from an observer, the sound waves will appear to have a lower frequency and a lower perceived pitch.
In summary, while the speed of sound remains constant regardless of the motion of the sound source or listener, there may be changes in the perceived pitch due to the Doppler effect.