The spelling of "Gillby" can be broken down into three distinct sounds. The first sound is "g" pronounced as /ɡ/ and then followed by "i" pronounced as /ɪ/. The last sound in "Gillby" is "lby" which are three sounds pronounced as one. "L" is pronounced as /l/, "b" is pronounced as /b/ and "y" is pronounced as /i/. So the correct phonetic transcription is /ˈɡɪlbi/. Remembering the IPA phonetic transcription will help you to pronounce "Gillby" correctly.