Note: with all character written in Hiragana having the "tenten" - double upper comma like, it's supposed to be understood as they are emphasized.
Given that Sendai is crying, it's a bit of both - the voicing of a consonant is what the tenten gives, and also what forcing the sound through tears, so I'd hazard to say that the ka is indeed a ga. You can't voice a na though.
This comic is immeasurably funnier after seeing all three light cruisers in their Search And Destroy modes.
-KA LOV-Pure HeartedJuvenile!Naka-chanThank yooou!Yes!
Yes!Light CruiserUltimate sparkling!Next is of course that song -Yes!
Yes!Everyooooone!Wow~NakaNAGAA!