The traditional way to say 'Hello' in Sikhism is Sat-sri-akal.
Although, some people argue that this belongs to the Jahkara and shouldn't be used to say hello so they say this instead:
'Vaheguru ji ka khalsa,
Vaheguru ji ke fateh.'
Adding to the answer above:
As per the orders of Guru Gobind Singh ji, every Sikh must greet the other Sikh by saying "Waheguru ji ka khalsa, Waheguru ji ki fateh."
Most of the people say "Sat Sri Akal" which is not OK as per "Sikh Rehat Maryada."
Sikhism is a religion, not a language. Sikhs say goodbye in whatever language they speak.
you say welcome aboard I don't know why but that seems to be the case
you are welcome
How do you say you’re welcome in Apache
To say "welcome" in Tlingit, you can say "Yak'éi."
In Berber, you can say "Tanmirt" to say "you are welcome."
To say "welcome" in Choctaw, you would say "yakoke."
To say "you are welcome" in Kurdish, you can say "khosh amadi."
welcome
welcome
To say "welcome friend" in Lakota, you would say "Wóphila, kštó" which translates to "Welcome, friend."
to say you're welcome you would say 'de nada'