Jehovah's Witnesses believe that the conversations between God and the people are carried out by angels, but the angels are not mentioned in the Bible. They are merely assumed to be present, because no one has seen God. How accurate are the angels as messengers? Is it assumed that the angels carry God's word word-for-word or paraphrasing God's words?
This could probably be a lengthy answer, but it would be better to summarize one core belief, which should easily answer the remainder of your question.
Jehovah's Witnesses believe by a number of scriptural proofs that Christ himself is an angel, the highest ranking one, and he is the primary means that through which the speaking between God and man occur.
Since "angels" are the subject here, there is for instance Jude 1:9 [Amplified Bible]:
9 But when [even] the archangel Michael, contending with the devil, judicially argued (disputed) about the body of Moses, he dared not [presume to] bring an abusive condemnation against him, but [simply] said, The Lord rebuke you!
This of course is stated on the basis that Jehovah's Witnesses understand that Michael is the same person as "Jesus" (Michael being his pre-earthly angelic name).
Contrast this to how God himself deals with Satan's taunts regarding one of his servants in the first chapters of Job - the reaction is far more authoritative and altogether different. Simply, there is a stark difference between how God (not an angel) and Jesus (an angel) deal with Satan's challenges.
So if Jesus, the "Firstborn of creation" (Proverbs 8:22) is an angel, and he is also called "The Word", the primary means of which God's word is transmitted to us, then that is probably the first and foremost answer to your question.
Then there is Hebrews 2:2:
2 For if the message given through angels [the Law spoken by them to Moses] was authentic and proved sure, and every violation and disobedience received an appropriate (just and adequate) penalty,
Without a complicated run-down of every scripture, Jehovah's Witnesses understand that God's angels are very obedient (indeed perfect) and just like human copyists of scripture, have transmitted messages exactly as directed. Of course Jehovah's Witnesses do not put a huge amount of undue attention on angels themselves, and follow the example angels set in directing glory go God alone. Revelation 19:10:
10 Then I fell prostrate at his feet to worship (to pay divine honors) to him, but he [restrained me] and said, Refrain! [You must not do that!] I am [only] another servant with you and your brethren who have [accepted and hold] the testimony borne by Jesus. Worship God! For the substance (essence) of the truth revealed by Jesus is the spirit of all prophecy [the vital breath, the inspiration of all inspired preaching and interpretation of the divine will and purpose, including both mine and yours].
In a looser sense, the word angel also means "Messenger" and indeed many messengers are involved in the transmitting of God's word - including humans in the spreading of the word throughout the earth.
I have no doubt that there is a more complete answer than this to be made, but this is a general overview. Its most important to state that Angels are not the focus of JW beliefs, and they do not receive undue attention.
I have been one of Jehovah's Witnesses for over 30 years. Here is a short answer in my own words:
The bible sometimes says things that God did, but really means that he was the 'architect' of that action but had a 'laborer' actually do that action.
For instance: Genesis 1:1 says that God created the heavens and the earth. But later in the bible (Colossians 1:16, 17; John 1:3, 10; Hebrews 1:1, 2) it gives more detail showing that he used his son Jesus as a "master worker".
So, with regards to God speaking through angels... In Exodus 20:1, talking about the Ten Commandments, it says “God proceeded to speak all these words.” But, later in the bible (Galatians 3:19) it says “It was transmitted through angels by the hand of a mediator.”
So, it seems likely that other times when the bible says that God spoke something, it may have been through an angel also.
Here is the long answer from the 1990 Watchtower:
Watchtower 1990 5/1 p. 30
Questions From Readers
▪ Did Jehovah God speak to Adam directly, or did he speak through the Word, the only-begotten Son of God?
The Bible does not give us an explicit answer to this question. While God could have spoken directly to his perfect human son in Eden, likely He communicated with Adam through the Word.
The Bible often speaks of God’s doing things when he actually did them through one or more angels. For instance, Genesis 1:1 tells us: “In the beginning God created the heavens and the earth.” Were that all the Bible said about the origin of the universe, we would conclude that God created it directly, as if with his own hands. The Christian Greek Scriptures, however, enlarge our understanding. We read: “By means of [the Son of God] all other things were created in the heavens and upon the earth, the things visible and the things invisible . . . All other things have been created through him and for him.” (Colossians 1:16, 17) Other texts confirm the Son’s role in creating the universe. (John 1:3, 10; Hebrews 1:1, 2) Still, his role was as a workman subordinate to Jehovah, who originated, empowered, and directed creation.—Psalm 19:1.
God said to the first man: “From every tree of the garden you may eat to satisfaction.” (Genesis 2:16, 17) Jehovah did not need some mechanical or electronic device, such as a megaphone or a shortwave radio. As The Watchtower of August 1, 1989, said: “The man saw no one doing the speaking. The voice came from the invisible, the unseen realm, and it was addressing him. It was the voice of the man’s Maker, his Creator! . . . The man needed no modern scientific radio receiver to hear the divine voice. God conversed with him directly.”
Did God speak through an angel, perhaps the Logos, who became Jesus? That is quite possible. While not being dogmatic, C. T. Russell wrote: “Jesus perhaps was the Representative of God in the Garden of Eden with Adam.” (The Watch Tower, February 1, 1915) God’s firstborn Son long served in the exalted capacity of his Father’s “Word,” or Spokesman, to angels and men. (John 1:1; 12:49, 50; Revelation 1:1, 2) So even if the Genesis account conveys the impression that God spoke directly to solitary Adam, that does not rule out His speaking through an angel, including the Word, Jehovah’s heavenly Son. Especially would this be so considering that Jehovah used the Logos to create man in the first place, and this one ‘was fond of the things involving the sons of men.’—Proverbs 8:22, 31; John 1:3.
Consider, for example, the occasion when Moses went up on Mount Sinai. Exodus 19:21-24 relates: “Jehovah now said to Moses . . . At this Moses said to Jehovah . . . However, Jehovah said to him.” Then the account of the giving of the Ten Commandments is introduced this way: “God proceeded to speak all these words.” (Exodus 20:1) Does that sound as if God personally spoke the words of the Law? Such an impression could find support in that we are told that God spoke to Moses “face to face.”—Exodus 33:11.
Still, we have further revelation on this. The apostle Paul wrote about the Law: “It was transmitted through angels by the hand of a mediator.” (Galatians 3:19) Later, Paul specifically contrasted the instructions God provided in the Law and what Christians received through Jesus: “If the word spoken through angels proved to be firm, and every transgression and disobedient act received a retribution . . . , how shall we escape if we have neglected a salvation of such greatness in that it began to be spoken through our Lord [Jesus] and was verified for us by those who heard him.” (Hebrews 2:2, 3) So God did not speak the words of the Law with his own personal voice, nor did he use the Logos. Rather, he chose to use other angels.
What is the basic point, though? Often when we read of God speaking to humans, we note that he did so through obedient spirit creatures who spoke for him. (Compare Genesis 18:2, 3, 33; 19:1; Exodus 3:2-4; Judges 6:11, 12, 20-22.) Jesus’ designation as the Word suggests that he was one whom God often used to communicate with his other creatures. Did that include God’s perfect son Adam? Most likely.—Luke 3:38.
It is true that when the Logos was later on earth, the Father three times spoke audibly so that this “last Adam” could hear. (1 Corinthians 15:45; Matthew 3:16, 17; 17:1-5; John 12:28-30) On these occasions, why should God speak to or about his precious Son through an intervening angel? More logically, Jehovah would speak directly; his perfect Son, and even imperfect humans nearby, heard God’s own voice. So when the perfect man Adam was created, his loving Father could have dealt directly with this perfect new creation. However, in view of the foregoing, it is likely that he used the Word.
I am one of Jehovah's Witnesses. It sounds like you are asking if we believe that angels will walk up to us and give us messages from God. That is not one of our beliefs.
Here is an excerpt from one of our publications:
No longer do these mighty angelic ones appear visibly in behalf of Jehovah’s servants on earth, as when they delivered the apostles from prison; nevertheless, God’s servants are assured of the ever-present, invisible protecting armies, as real as those that surrounded the prophet Elisha and his servant. “He will give his own angels a command concerning you, to guard you in all your ways.” Yes, “the angel of Jehovah is camping all around those fearing him, and he rescues them.”—Ps 91:11; 34:7 NWT (Source)
If you want to know what we believe there are only two ways to find out:
http://www.jw.org/en/jehovahs-witnesses/ (Read our "About" page.)
Ask one of Jehovah's Witnesses. (Seriously, to ask anyone but a JW is like asking a Spanish teacher to teach you German. )