When you are intending on moving to the United States there is quite a lot of paperwork to do before you can actually board your airplane and wave goodbye to your country of origin. You have to ensure that all your documents in your mother tongue are translated into English by using a translator who understands the USCIS translation service requirements.
You are not allowed, as the main applicant for any type of U.S. visa, to translate your own documents even though there may be no doubt that you have the competency to do so. You must use someone else who is an experienced translator for the pair of languages involved. There is good reason for this requirement because there is an awful lot of small print on a document that needs translating.
For example, some documents have a seal or a stamp with a signature embedded in them and even some words around or on top of them which need to be translated. This can really only be translated by a competent USCIS translation service translator who understands the nuances of both languages so the translation will be accepted by the officer in charge of visas at the USCIS when your visa application is received.
It is quite understandable why the USCIS has strict requirements in relation to the accepting of documents for immigration purposes. They want to be sure that people entering the United States are who they say they are and that any skills they have or job offered will not take away job opportunities from United States citizens. It is virtually impossible for an immigration officer to understand all the different languages immigrants speak so they put the responsibility on to the applicant to ensure a valid translation of all required documents is completed.
To ensure the translation matches the USCIS translation services requirements each translated document has to include a signed statement by the translator stating the translation is accurate. This is considered to be sufficient evidence by the USCIS. Of course, if random checks are made and some inaccuracies are discovered you will be asked to get an accurate translation which will delay your move to the United States.