If its really as tough to translate or understand as some say because of its archaic sanskrit, then how so many people, including some foreigners have translated it in english ?
Rig Veda I.164.45 says
चत्वारि वाक परिमिता पदानि तानि विदुर्ब्राह्मणा ये मनीषिणः | गुहा तरीणि निहिता नेङगयन्ति तुरीयं वाचो मनुष्या वदन्ति ||
Four are the levels of speech that are measured, these the wise sages know. Three hidden in secrecy, they cannot manipulate, only with the fourth level of speech do humans talk.
Rig Veda itself says, there are 4 types of speech and only one(1) is known to humans. The remaining 3 speeches will be so cryptic and a true Yogi will know how to understand them.
Nirukta, written by Yaska, is one of six Vedangas which are very essential to completely understand Vedas. Nirukta is the the study of origin of Sanskrit words i.e etymology which is very useful for understanding and interpreting Sanskrit words.
There are at least 400 words, used in Veda, which were not understandable even to Yaska.
Anyone, with sufficient knowledge in Sanskrit, like Max Müller, can translate the outer meaning of the mantras. However, the mantras of Veda contain multi layered meaning. Only a sage can decipher the inner meaning.
Majority of the mantras of Rig Veda were considered to be apaurushEya, not of Human origin. So the mantras that were revealed to the ancient seers, were composed in an esoteric manner, mainly to make them un-understandable to a casual reader. Only a serious reader, with the guidance of another sage, can understand the inner meaning.