Do you have heavy ears?
Now, how might we translate the meaning of the Hebrew of Is. 6:10 to English so that readers of a translation will understand the metaphorical meaning just from reading the translation? That, after all, is the purpose of a translation, to allow speakers of one language to understand what was said in another language.
Following are some English versions which accurately translate the meaning of the Hebrew idiom to English:
Make these people ... plug their ears. (GW)The following might make sense in English to some people:
make their ears deaf (TEV, NET)
Shut their ears. (NCV)
Make them stop up their ears (CEV)
Close their ears (NLT)
deafen their ears (HCSB)
stop their ears (NRSV)but it would make more sense to me if it were worded as "stop up their ears."
In English it is possible to be "dull of hearing" or to have "dull hearing," but I don't think we can communicate the meaning of not hearing by saying that someone's ears themselves are "dull" as in these versions:
make their ears dull (NIV, TNIV)Finally, I am quite certain that the following wording is inaccurate. That is, I don't think it communicates any meaning in English other than a literal meaning that someone's ears weigh a lot:
Render ... their ears dull (NASB)
Make ... their ears heavy (KJV, RSV, ESV)I would be glad for fieldtesting to prove my claim of inaccuracy wrong.
If a translation wording does not communicate the meaning of the original biblical text to its users, it is not an accurate wording. It would be great if we could literally retain this Hebrew idiom in an English translation, but doing so alters the original meaning and that is a form of inaccuracy. Translating the figurative meaning of the Hebrew into English which has the same meaning is accurate translation. It is not so-called "interpretive translation" as the term is used pejoratively these days. There is no personal interpretation of the Hebrew idiom involved in translating its meaning to English. English Bible translators agree on the meaning of the idiom.
Literal or essentially literal translations are fine whenever they accurately communicate the meaning of the biblical text to translation users. They are inaccurate when they do not. Similarly, more idiomatic translations are inaccurate whenever they do not accurately communicate the meaning of the biblical text.