These are signal flags, used to communicate with ships. The flag is in the middle. The speech bubble with the letter is the letter that the flag represents. The other speech bubble is its ICS meaning. The purple text underneath the flag is the flag's name, following the NATO alphabet.
International maritime signal flags are standarized flags used to communicate with ships. The principal system of flags and associated codes is the International Code of Signals. Various navies have flag systems with additional flags and codes, and other flags are used in special uses, or have historical significance
