What is the difference between responding with "Alaikum Salaam/علیکم السلام" and responding with "Walaikum Salaam/وعلیکم السلام"? Is it wrong to say "Alaikum Salaam" in reply to "Assalamu Alaikum"?
Well you can answer:
Alaikum as-salam عليكم السلام or wa alaikum as-salam وعليكم السلام
Both are perfectly fine and good answers!
Also available are the singular forms:
- 'alaika as-salam عليك السلام and
- wa 'alaika as-salam وعليك السلام
and also to repeat with the same word
- 'alaika as-salam السلام عليك ... etc. all this five expressions can be referenced from the sunna, even if i only referenced one!
But what you should never do is greet or begin greeting by saying 'alaika ('alaikum) as-salam see here. Note that this has it's origin in Arabic costumes of the time as they used to greet or send a greeting to a dead person this way, as the poet said:
عليك سلام الله قيس بن عاصم * ورحمته ما شاء أن يترحما
فما كان قيس هلكه هلك واحد * ولكنه بنيان قوم تهدما
while the Prophet (Peace be upon him) in his sunna also used the wording with "as-Salaamu alaikum السلام عليكم أهل دار قوم مؤمنين" when visiting the gravyard. So according to a quote of al-Khattabi in tuhfat al ahodi (a commentary on sunan at-Tirmidhi) on this hadith. Muslims don't make a difference between greeting dead and living people.
The only difference between the two possibilities you mentioned is the letter/character "Waw" or "wa", "و" this additional character gives a direct answer to the greeting, as when you say
- as-salamu 'alaikum = peace be upon you
you express a kind of wish, therefore saying
wa 'alaikum as-salam = peace be upon you too or literally translated and peace be upon you
('alaikum as-salam = peace be upon you)
As an answer makes a small but meaningful difference! As you somehow "include" the greeting of the other person in your answer!
And Allah knows best!
In the name of Allah, the most compassionate, the most merciful
Briefly speaking, typically, the first person who intends to say hello (as a greeting), he or she says:
- Assalamu Alaikum/Alaik
But the second one who want to reply to his or her Salam, tells:
- Alaikum/Alaika Salam (which demonstrates being the second part who is saying back his/her hello
Otherwise seemingly you can use both of these two forms in replying, although "Alaikumo Salam looks to be more accurate/formal in compare with the other form (in reply).