Open your preferred digital audio program, such as Pro Tools, GarageBand or Cubase. If you don't have a digital audio program, download a free one such as Audacity that lets you record, edit and convert audio. They lack the sophisticated functionality of professional programs, but are perfectly adequate for simple audio editing. Visit the download page for your preferred program and follow the instructions.
Import the audio file to be converted to multitrack. The specific command sequence varies according to which program you use, but the import command is typically located in the "File" menu. Select the appropriate file from the browser. This opens the audio file as a waveform graphic in the digital audio program.
Click "Play." Listen to the track and make notes of the times where you'd like the track split. For example, if the audio has a natural pause or the speaker changes topics, write down the time.
Scroll the audio to the first split point. Drag the navigation bar at the bottom of the screen to the left to go forward and to the right to go backward. Use the time bar at the bottom of the screen so you can see which point in the audio you are at when scrolling.
Select the "Trim" tool. This is located in the "Tools" menu on Audacity, Pro Tools, Logic and Cubase. It is typically identified by a scissors icon.
Click the cursor on the audio graphic, under the time noted earlier, for example "30 minutes, 23 seconds." Use the peaks of the waveform graphic as a guide so you don't trim the audio in the middle of a word. The peaks represent volume. Aim to trim as close the final peak in the section. Repeat this process for each section of audio until you've split it into sufficient tracks.
Click on the first section of audio to highlight it. This assigns subsequent commands to that section of audio rather than the entire audio.
Export the selection in your preferred file format. The export command is typically located under the "File" menu, just below the import command. When prompted, select from "Wav," "MP3" or another file type. Then name the file, such as "Dad's Wedding Speech, Part 1." Repeat the export process for each file, naming them sequentially.