The correct spelling of "picks speed" is "picks up speed" with the phonetic transcription /pɪks ʌp spi:d/. This phrase means to accelerate or increase in speed. The word "up" is crucial in understanding the intended meaning of the phrase. Without it, the phrase "picks speed" could mean something entirely different, such as someone picking the word "speed" out of a group of words. Therefore, it is essential to use the correct spelling and phrasing in communication to avoid confusion.