"My son needs a small suitcase."
Translation:Mi hijo necesita una maleta pequeña.
DL will be trying to teach 'correct' language rather than every form of slang. Using "mijo" instead of "mi hijo"would be the equivalent of using "gonna" instead of "going to". It's something you may be capable of understanding and using well when you're fluent but not when you're starting out learning.
Actually I think the reason, "mijo", isn't correct is because in this sentence, is because "mijo" is a term of endearment. It is something you would call your son, a slang way to say "my son" when you are talking to him, not about him. You would never say, "mijo necesita..." to express to someone else what your son needs but you might say "mijo, necesitas..." when you are expressing to him what he needs. Does that make sense?
You match the gender of the adjective to that of the noun it describes. Since 'maleta' is a 'feminine' noun, the adjective has to be 'feminine', therefore you use 'pequeña' not 'pequeño'. BTW, you need to use a Spanish keyboard (download one) or hold the relevant key on your mobile to get alternative letters. For the 'ñ', hold the 'n'. Remember, 'ñ' is as much a different letter from 'n' as 'm' is.
1) you need to match the 'gender' of the adjective to that of the noun, so it needs to have an 'a' not an 'o' at the end because 'maleta' is 'feminine'.
2) you need 'ñ' not 'n' in the spelling. No, this is not something that can be ignored. They are two different letters as much as 'm' and 'n'.
Verbs change form based on which person (1st = self 'I'; 2nd = person you are talking to 'you'; 3rd = person you're talking about 'he / she') and number (I / you singular / he or she vs we / you plural / them)
- 'necesito' is the form of the verb 'necesitar' for first person singular
- 'necesita' is the form for third person singular
Are you unable to see the answers further up the thread? There are already good answers towards the top. Try around here: https://forum.duolingo.com/comment/27675092?from_email=comment&comment_id=46080333
It's the "pequeña" that's the issue there - ñ is as different a letter from n as m is. If you're using a phone, hold down the n to have alternative letters, including ñ, come up and slide your finger over to that letter. Alternatively, enable a Spanish keyboard layout. On a regular computer you'll need to download or enable a Spanish keyboard layout and switch to it.