The tone of Chesterton's poem, "The Secret People", written at the turn of the last Century, 1908, when Western European powers were competing fiercely for God, Gold & Glory, (not necessarily in that order), reminds me of the following clichés:-
--- Stiff upper lip;
--- Don't mess with us;
--- The English Bulldog;
--- Barking dogs never bite,
translated into poetic language by Chesterton.
Thus my attempt, (to hopefully capture "We are the silent people, who have never spoken yet"), is:-
沉默任我族, 从未开口过 which better conveys a sense of "silent / stoic defiance" which could easily turn into something explosive given the right catalyst, which is what Chesterton's poem seems to imply, i.e. the "silence" of the British people does not mean "weakness"
I also opted for 从未开口过 as 开口 gives a strong combative flavor / a kind of veiled warning, (as opposed to 说话 which is too "laidback"), i.e. 开口 implies something like, "don't make me open my mouth, for if you do, you will surely regret it"
Further than this, 开口 also has the added feature of not just saying something, but saying something with a critical / commentative element, whereas 说话 is just 说话 -- "speaking"
As for a sense of "the" in Chinese, Chesterton's poem does emphasizes "the....people" to give a certain unique racial quality in order to set apart, up till then, the "silent" British people.
Does Chinese have such kinds of emphatic language device as "the"?
Not to my knowledge. The best I could do is to say 我族 which does convey a sense of "communal / trial belonging", something like "We the people of....."
In reply to your Comments:-
1. "...explain 沉默任我族, I don't understand how 任 is working here...."
The word 任, like any word in any language, has multiple meanings and thus multiple usages. The particular meaning I attach here is "to constitute", "to appoint to be or to become a certain definable entity", as in "made up of...."
Thus 沉默任我族 means "Our clan is constituted or is or becomes an entity where "silence" defines us"
2. "Could you say 沉默任我 民 族,从未开口过 which is close to the original meter?"
The sought for characteristic of Chinese idiomatic writings is one of extreme economy of words while maintaining the intended core meaning(s). A good classical example is the “Three-Character Classic,” or Sān Zì Jīng "三字經". The fact that you know / understands that 我族 means, in long form, 我民族 precisely makes my point.
Also, my phrase 沉默任我族, 从未开口过 is, in Pinyin, Chén Mò Rèn Wǒ Zú, Cóng Wèi Kāi Kǒu Guò
As you can see, Zú in the first phrase has an up-tone, and therefore the ending of the second phrase should have a down-tone, namely, Guò, in order to comply with the rhythmic intonation of poetic language to a satisfying cadential / harmonic resolution.
Finally, the Chinese version has exactly 5 words in each phrase which is the common form of rhythmic pacing.
Try saying 沉默任我族, 从未开口过, and 沉默任我民族,从未开口过 in a rhythmic fashion? You will find that after saying 沉默任我民族, the second phrase 从未开口过 seems disconnected from the first phrase and somehow irrelevant.
The phrase 沉默任我族 feels like it's suspended in the air, and thus urgently requires 从未开口过 to resolve the whole idiomatic phrase harmonically.