words in music

I thought the sound/music terms confusing.

like 'pitch', 'tempo',  fine to me,  and then it  comes 'speed' 

For instance in the open source app "Audacity", in the "effect" drop down menue. There are options:

• pitch- change pitch without changing tempo,
• or tempo- change tempo without changing pitch.
• but the speed--change speed will change pitch and tempo.

 Is it not that changing tempo is changing music playing speed?  By changing tempo, the playing speed/frequency of each note is changed-->does this not affect the pitch?   We know that the sound tones, i.e. pitch,  is due to different vibration frequencies of vocal cord.

Can anyone explain these music terms?

• pitch
• tempo
• speed
• rhythm
• reverb
• balance