Turn off voice tags

Touchscreen phones simplify the wireless world, especially when combined with voice activation. Although making calls using voice commands was an option before touchscreens became available, the method used to set up this feature is different than it is for non-touchscreen units. It can take time to master the set of procedures that will get the feature working.
Step 1
Create a voice tag. Touch "Contacts" on the today screen. This opens the list of contacts on your phone. From here, do one of three things: you can hold your finger on the desired contact and then tap the "Add Voice Tag," you can select the desired contact, tap on "Menu" and then "Add Voice Tag," or you can tap the desired contact to open their personal screen and then hit "Menu" followed by "Add Voice Tag."
Step 2
Record the voice tag on your phone. Touch the phone number to which you wish to add a voice tag then touch the "Record" button. Record your voice tag for that contact. An icon will be displayed to the right of the number when the voice tag is complete. You can listen to your voice tag by touching the "Play" button on the screen or you can delete it to record a new one.
Step 3
Make a voice tag for a program. Tap the "Start" button on the phone. Go to "Settings" and then the "Personal" tab followed by "Voice Speed Dial." Choose the program for the voice tag and record the voice tag in the same manner as you did for the contact. To open the program with the voice tag, tap "Start," "Programs" and then "Voice Speed Dial."
Step 4
Launch a program or make a call. Make a call by tapping "Start" followed by "Programs" and then "Voice Speed Dial." You will hear a beep. Say the voice tag you recorded for the person you wish to call. You can open a program via the same procedure (by speaking the voice tag created for the program).
Step 5
Check the voice tags you created. Tap on "Start," "Settings," "Personal" tab and then "Voice Speed Dial." A voice tag tab appears and displays a list of your voice tags.

Delete some SMS and you will have more free memory to add a tag to a contact that you must save on the telephone and not on the SIM

Quick answer, you don't. I had the same problem so I emailed Nokia UK and got a reply back from them, saying that voice command/dialing is not a feature of the C3-00. But they hope to sort it out in the future.
This is what they sent...

Thank you for contacting Nokia Care.

We understand that you would like to use voice tags or voice dialling on your C3 device. We regret to inform you that there is no means as of the moment to do this. However, Nokia is currently working on this issue and will come up with an update in the near future to support the varying needs of our customers.

For future reference, please feel free to check our website. Kindly refer to the link below:

http://www.nokia.co.uk

You may also call our Customer Care Hotline at 0845 -045-5555, Mon-Fri 9am - 7pm (except bank and public holidays)

Please do not hesitate to contact us again if you have any questions.

I'm unsure if you are speaking of voice recognition or voice services. The "call options" menu will customize settings.

To remove voice tags/commands from the phone select: menu>settings>call options>erase voice dial>yes.

To disable voice answer select: Menu>settings>call options>voice answer>disable.

To utilize only messaging services you need to contact Virgin Mobile, 1-888-322-1122, about text and data only plans.

went 4 new software

To switch on voicemail you need to dial 1750 this is a free call and to turn off dial 1760

if it a nokia u go in ya phone book selct options and scroll down to add voice tag

hi.....im andrei.your problem is very easy to solve...... try to change the microphone...^^

i need to say u should save the voice tags in a silent place with keepin the phone at a smalll distance from mouth . say the words cleraly as u are u can repeat the word in the same clarity

nraj is correct but could have been a bit clearer upon his solution, if you goto nokias website there is a link to update the phones firmware.
it will download an app to your computer that will find the phonew and then update it automatically for free.
if however you took the phone to a shop they may charge for the priveledge