Nikaah & Marriage Issues

Bridegroom mumbling some words in Arabic at the time of nikaah

Q: Was this nikah valid?

The Imam told the bridegroom clearly to many witnesses in the masjid that ‘do you accept so and so’ upon which the bridegroom mumbled a few words in Arabic (as the bridegroom was a Talib Ilm so probably wanted to say the Arabic phrase). The mumbling could be heard by the audience.

Does it matter if the audience didn’t understand what was being said by the bridegroom?

Girl under 18 getting married

Q: I am 17 years old. My mother has passed away last year and I am living with my mamo and nano. I am totally burdened to them. My sister got married last year. They want me to also get married. I am biologically 19. My age was change in childhood. Can I get my nikaah since I've heard that girls under 18 cannot get married?

Waleemah and secret nikaahs

Q:

1. I have been in a secret nikaah for 10 years. As such, we didnt do walima. My immediate family now know about my nikaah. Is it possible to do a walima so long after a nikaah?

2. Also, according to my husband he says that because I'm a secret wife, I have no right to inheritence according to Islam. Kindly confirm/clarify.

3. I must point out that 5 years ago, his first wife learnt about us. She was devastated but wanted to meet me. She has accepted his nikaah to me but insisted that the nikaah must still be kept a secret and set specific rules for us. So...is our nikaah still a secret one and is it justifying for her to set such rules and ask that the nikaah still be kept a secret?

Tying one's tubes after pregnancy

Q: I have psoriatic arthritis. It gets worse after each pregnancy. After my 2nd child (I have 2), the bones in my feet and knees have become bad so I can only read salaah while sitting on a chair. I can't go on my knees at all as it causes excruciating pain and I can't wake up. In my case, would I be allowed to tie my tubes after a 3rd baby?