Assuming you have a Microsoft Windows machine (it also works on Linux, but the software install procedure is slightly different for that platform and outside the scope of this article), you have several solutions available for recording audio, editing it and listening to it.
When recording any audio, voice or otherwise, this is the basic process from end to end:
record the audio (the raw recording) -- using a microphone for simple voice recordings
edit the audio, if desired:
cutting out the start and/or end silences
cutting out some parts of the recording which you do not want to end up in the final result
reduce background noise
normalize the sound, i.e. tweak its loudness to standard / optimal levels
save the (edited) recording
export the (edited) recording to an easily playable file format (MP3)
send / carry the MP3 file to the listener
play the MP3 audio file (listening to the recording)
Steps 1-4, i.e. recording the audio is done in an audio editor, while you can use email (attachment), an USB stick or other means to perform step 5, while step 6 can be done in another instance of the audio editor, but the listener doesn't have to: any MP3 player will work fine (e.g. foobar2000).
We are going to use a free Open Source based solution using the Audacity application.
It can be downloaded from the Internet and installed on your machine with ease and has both a relatively simple interface while providing a lot of power for when you have completed your rough recording and need to edit it (cutting, processing, exporting to MP3 format).
(See also the Audacity website FAQ (Frequently Asked Questions) section.)
When you have downloaded the application from the Audacity website, you can run the installer. It is a simple process, where all you have to do is click the 'Next' button a couple of times until you 'Finish'. These screens will show up while running the installer:
When you launch Audacity for the first time, the following dialog window may show up if you have other music-related software installed on your machine (VST plugins); you can hit 'Cancel' here if you do not want Audacity to include these plugins (you don't need them for the basic recording and editing processes):
Before you will be able to produce an MP3 file using Audacity, you will also need to install the MP3 codec (encoder/decoder) available here. This is also mentioned at the Audacity website, incidentally.
(For another description of this process, see http://www.howtogeek.com/howto/40274/how-to-add-mp3-support-to-audacity-to-save-in-mp3-format/)
When you run that MP3 installer, these dialogs will be shown. Again, it's clicking 'Next' until you 'Finish'...
Once both these installers have completed, Audacity will be available in your Windows Programs menu and will be able to export to MP3
When you start Audacity from the Windows Programs menu (a.k.a. Start Menu), the following screen will appear:
For most machines you won't have to configure anything as the default microphone and speaker channel configuration is used. You can change those in the right panel at the top; for more information see also the Audacity User Manual.
We simply start recording by pressing the record button indicated below:
When you talk, your microphone should pick up the sound and sound should appear visually, as shown below. The red line in the recorded track is the 'current time' cursor. The sound level is also visible as a red VU bar in the top panel. (In the image below we record stereo but only the left channel has a microphone; you can also instruct Audacity to record a mono track, but the screen below shows what happens when you hit the record button immediately after installing Audacity without any further configuration.)
The recording is stopped when you hit the stop button as shown below. (You can hit the play button to reply the audio track to listen to your recording. This is also useful when you edit the track afterwards.)
You can monitor your microphone input level while the application is not (yet) recording the audio by clicking on the VU bar drop arrow and selecting 'Start Monitoring' in the menu as shown below:
... after which the current microphone input sound level is visible in the VU bar in red:
This is described in more detail in the Audacity manual, but you can select a section of the audio track by dragging the mouse over it (dragging = press mouse button, move mouse, then release mouse button; hovering = move mouse without clicking any button) and then selecting the command you wish to apply, e.g. crop.
See the Audacity online tutorial for detailed workflow info: http://manual.audacityteam.org/o/man/tutorial_your_first_recording.html
Note / Tip: when you have removed chunks of audio from the recording, you can move the remaining block(s) of sound recording to the start of the track by clicking on the Time Shift Tool icon as shown below, after which dragging the mouse does no longer select a strip of audio but simply moves the audio blocks in the track timeline as shown below. (Note: Hovering the mouse over the icons shows the tooltips listing their function as shown in the next screenshot.)
When you select a track (doubleclick on the track info at the left of the track to select the entire track at once) you can then execute the command Track -> Stereo Track to Mono:
which will mix the stereo to a single mono track. (Note: here you may observe that the recorded audio is halved in volume because the left track is mixed with silence in the right track. We will correct the audio sound level anyway using the Normalize edit command.)
Normalizing the track ensures that the sound level is standardized and boosts your soft recording while making sure that the peaks are not clipping. Note that overloud (overdriven) recordings will be slightly reduced in sound level, but normalization cannot remove clipping from the original recording.
When you select a track or chunk of recording, the selected audio is normalized by the Tracks -> Normalize command, which will pop up this dialog. Do not change these settings, simply click OK.
To reduce noise, Audacity uses a noise profile which is obtained by selecting a range in the recording which should be otherwise silent, i.e. only contains noise. (Tip: several seconds of recorded 'silence' works best so let the recording run for a few more seconds at either the start or the end if you plan on using noise reduction.)
Here we have selected a 'silent' section at the end of the recording:
... and by clicking Get Noise Profile we instruct Audacity to analyze the noise in the selected silent part of the recording:
Now you can select the audio to process, in this case the entire track, and apply the noise reduction:
This time we hit 'OK' in the noise reduction dialog panel (you may tweak the settings but I find that the defaults work fine, so only twiddle those settings when you have become very familiar with this process):
... and you may observe that the audio track shows much less noise visually at least. Of course the proof is in listening to the edit by playing the track. Note that strong noise reduction and/or incorrect noise profiles (e.g. when you selected an audio chunk with recorded speech included for Get Noise Profile) can produce ugly results so listening to the result is advised.
When you have finished the editing (if any editing was necessary) you should save the recording to disk. Audacity saves the recording in its own AUP format (Audacity Project), which stores the recording and its audio tracks exactly as-is. (File -> Save)
When you select the File -> Save menu, this alert box (dialog window) will show up; you can tick the checkbox to not have it show up ever again:
Tip: Audacity saves its projects in your user Documents (a.k.a. My Documents) folder/directory by default. It is advisable to keep things a little organized and first create an empty subdirectory (New Folder) where you then store this and any further recordings, thus keeping the audio recording work separate and identifiable.
When you have created such a subdirectory, you should give the recording (project) a name. (Hint: something more useful than the 'test1' name in the screenshot is suggested; use a short name which describes the recording and maybe include the date as well (more editing later on will change the project file date itself), e.g. 'training words exercise A 2013-03-10.aup')
For others who do not have Audacity installed on their computer or when you otherwise want to compress the audio for easy transportation and distribution, the MP3 file format is an excellent choice. As the install procedure above installed the 'LAME MP3 codec', your Audacity application will be able to export the recording to MP3 via the File -> Export menu entry:
Make sure to select 'MP3 format' in the Export File dialog:
and give the MP3 file a useful name (by default it will pick up the same as your project itself, which is fine: the project is saved as an AUP file, while this would create a MP3 file which can coexist with it without any trouble)
but before you click on the Save button in the Export File dialog you will need to configure the MP3 export process by clicking on the Options button first, after which the dialog below appears. Make sure to select the settings as shown in the next screenshot to ensure that the MP3 export file has the highest quality encoding:
Now it's time to click OK and then Save in the Export File dialog:
As MP3 files can contain tags describing the audio track, another dialog pops up, which you can leave empty:
And that concludes the export process, producing one MP3 file next to your AUP project (file+directory). You can now send or copy the MP3 to pass it to other people.