It is technically impossible to send a 10,000-character message. TeamSpeak commands are limited to 9203 bytes.
Note that the client incorrectly counts escaped query characters (e.g. space) as two bytes, while the servers counts them as one byte in terms of the limit of the single parameter. This also exists for other limits like channel descriptions and offline messages. Offline messages are even limited by 4096 characters no matter what type.
Calculating the limit correctly (by still taking into account the 9203 byte command limit) however isn't that easy.