So, if you wanna make one without any sound then you type this into the console:
playerradio 1 "some text here"

But heres a list of sounds you can use when you make your own custom radio message (replace the 1 in the playerradio 1 "some text here" command with one of those sounds down below and replace some text here with your own text but do not remove the "):

DeathCry
SniperWarning
Radio.Compliment
Disagree
Agree
ScaredEmote
Radio.Thanks
WonRound
CoveringFriend
PinnedDown
InCombat
FriendlyFire
LastManStanding
KilledMyEnemy
SniperKilled
Radio.EnemySpotted
SpottedBomber
ThreeEnemiesLeft
TwoEnemiesLeft
OneEnemyLeft
Clear
GoingToGuardLooseBomb
SpottedLooseBomb
Radio.StickTogether
Radio.FollowMe
Radio.TeamFallBack
Radio.GoGoGo
WaitingForHumanToDefuseBomb
Radio.CoverMe
help
Radio.HoldPosition
Radio.Decoy
Radio.Smoke
Radio.Molotov
Radio.FireInTheHole
Radio.Flashbang
AgreeWithPlan
WonRoundQuickly
RequestReport
radio.cheer
HeardNoise
killedFriend
WhereIsTheBomb
TheyPickedUpTheBomb
GuardingLooseBomb
EscortingHostages
Guardian.Victory
Guardian.HalfwayThere
Guardian.RoundStart

Heres an example:

playerradio FriendlyFire "That better have been a mistake!"

Colors for the custom radio messages (copy the squares only):

 Default

White
 Green
 Blue
 Dark Red
 Gold
 Light Gray?
 Light Green
 Light Red
 Light Pink
 Pale Red
 Light Blue

BONUS!:


 (this isnt a color, but it puts your text on a 2nd line.)


Now, to make your custom colored radio message you gotta place one of the squares (or the bonus square) at the beggining of the ", then you write your stuff and end it with another " (without placing another square.).

Example:
playerradio 1 "
name has been permanently banned from official CS:GO servers."



Some pre-made custom colored radio messages:

playerradio 1 "
name has been permanently banned from official CS:GO servers."
playerradio 1 "

name has received in trade: M4A4 | Howl"
playerradio 1 "
name
has opened a container and found: AWP | Dragon Lore"
playerradio 1 "
 name abandoned the match and received a 30 minute competitive matchmaking cooldown."
playerradio 1 "
name
has opened a container and found: ★ Moto Gloves | Smoke Out"
playerradio 1 "
name
has opened a container and found: ★ Karambit | Lore"
playerradio 1 "RAINBOW"