The slang phrase "gat on the horn" means to make a phone call while carrying a gun. It is spelled "gæt ɒn ðə hɔːn" in IPA phonetic transcription. The "g" at the beginning is pronounced like in "get". The "a" in "gat" is a short vowel sound like in "cat". The "t" is pronounced with a soft "d" sound due to the following "n". "On" is pronounced like in "gone", and "the" is pronounced as a schwa sound. "Horn" is pronounced with a long "o" and a silent "h".