You can say "Tud yma, boi!" (tid uh-ma boy) which is what I'd say, or if you wanna use the proper word for "boy" in Welsh then it's "bachgen" but it's less of a mouthful to say "boi", heh.
Formal: Dewch yma. Dere 'ma.
Hogyn or Bachgen
Dewch i mewn
Dewch ymlaen
Rydym yn cyfarfod yma.
you can't translate englsish phrases into welsh as you can words... so instead you could say , "byswn i'n dwlu taset ti yma" = i'd love it if you were here
ha'u ki' heni = come here ha'u ki' heni ta'ahine = come here girl ha'u ki' heni tamasi'i = come here boy foki mai = come back
"You are Welsh" = Rwyt ti'n Gymreig
Mae'n hyfryd cael bod yma.
To say "come here" in Hawaiian, you would say " hele mai."
'I am English' in Welsh is 'Dwi yn Saesneg'
To say "come here" in Igbo language, you would say "bia nye."