The wavelength of a wave is expressed as:

Where:
is the wavelength of the wave
is the velocity of the wave
is the frequency of the wave
According to the expression above, the wavelength is directly proportional to the velocity (this means that if the velocity increases, the wavelength will also increase) and inversely proportional to the frequency (this means that if the frequency increases the wavelength will decrease, and vice versa).
Then, if the frequency
of the wave increases, the velocity (in this case called speed) and the wavelength will decrease.
Another way to approach this is:
In a division, if the denominator is greater than the numerator, the result will tend to be smaller.
Now, going back to the expression above, we are able to see that the wavelength
does not depend on the Amplitude. Hence, if we increase the Amplitude, the wavelength will not change, it will not be affected.