I go to Eucharistic Adoration nearly every Thursday and we sing the 5th and 6th verses every time. The fifth is the famous "Tantum ergo" verse. When we finished singing last week, I perused the other verses and noticed something remarkable: all the final characters in each stanza of each verse are assonant! As I may have explained before, while I love music, I only have scant musical talent. This means I am easily wowed by most musical accomplishment, as long as it "doesn't completely suck." So, to a real musician and/or songwriter, the assonance （諧音）of the hymn （聖歌）may seem trivial. On the other hand, I consider myself an amateur poet and a compulsive wordsmith, so I am hardly indifferent to the subtleties of rhyme and assonance. Given my credentials, the composition strikes me as a brilliant success.
I will now reproduce the lyrics, but indicate the pronunciation of the final characters:
1. 信友齊來歡呼讚吟 [yin]，吾主聖體無限情 [qíng]，救世羔羊聖血流傾 [qín]，贖世犧牲換太平 [píng]，天地大君榮王天庭 [tíng]，甘受苦難救我靈 [líng]。
2. 聖子降生自取人形 [xíng]，至聖童貞為母親 [qin]，三十三載天涯飄零 [lîng]，山野海角佈福音 [yin]，終身橫遭輕慢辱凌 [líng]，架上七言終其行 [xíng]。
3. 耶穌受難前夜晚上 [shàng]，偕諸宗徒聚華堂 [táng]，遵順古教禮儀習尚 [shàng]，宰殺羔羊分啖嘗 [cháng]，建立聖體罪債普償 [cháng]，洪恩長流澤萬邦 [bang]。
4. 真主真人萬世稱揚 [yáng]，麵形聖化成神糧 [liàng]，酒亦成聖血爵中藏 [cáng]，全信勿疑主榮光 [guang]，敬禮朝拜耶穌君王 [wáng]，無限深情滿人望 [wàng]。
5. 皇皇聖體奧蘊深玄 [xuán]，我眾匍匐主臺前 [qián]，羔羊聖牲新祭禮獻 [xiàn]，摒除古教棄舊典 [diân]，虔誠全信以至永遠 [yuân]，五官所缺信心堅 [jian]。
6. 聖父聖子聖神尊高 [gao]，至仁至善萬民朝 [cháo]，齊頌德能神恩豐饒 [ráo]，敬禮讚美共歡躍 [yùe]，天主聖三無限蘊奧 [ào]，永生永王享榮耀 [yào]。
(Can you guess how to say 阿們？)
Now here is an English translation of the hymn, which I have annotated for assonance and rhyme:
Sing, my tongue, the Savior's glory [A],
of His flesh the mystery sing [B];
of the Blood, all price exceeding [B],
shed by our immortal King [B],
destined, for the world's redemption [B?],
from a noble womb to spring [B].
Of a pure and spotless Virgin [C]
born for us on earth below [D],
He, as Man, with man conversing [C],
stayed, the seeds of truth to sow [D];
then He closed in solemn order [E]
wondrously His life of woe [D].
On the night of that Last Supper [F],
seated with His chosen band [G],
He the Pascal victim eating [G?],
first fulfills the Law's command [G];
then as Food to His Apostles [H]
gives Himself with His own hand [G].
Word-made-Flesh, the bread of nature [I]
by His word to Flesh He turns [J];
wine into His Blood He changes [J?];
what though sense no change discerns [J]
Only be the heart in earnest [J?],
faith her lesson quickly learns [J].
Down in adoration falling [K],
This great Sacrament we hail [L],
Over ancient forms of worship [M]
Newer rites of grace prevail [L];
Faith will tell us Christ is present [N],
When our human senses fail [L].
To the everlasting Father [O],
And the Son who made us free [P]
And the Spirit, God proceeding [Q]
From them Each eternally [P],
Be salvation, honor, blessing [Q],
Might and endless majesty [P].
Not a terrible effort, but perhaps you are as struck as I am by how erratic the assonance-scheme is. (Or perhaps my philistinism prevents me from seeing how the scheme is an instance of a genuine poetic device.) With the exception of xuán, diân, and yùe, I find all the assonance in the Chinese version to be much tighter. Further, if we represent the phonetic theme (A, B, etc.) of each verse (1–6) in the Chinese version, we have 1:A, 2:A, 3:B, 4:B, 5:C, and 6:D, compared to at least a dozen different phonemes in the English version. Granted, there may be a more rigorously assonant English version I have not cited, but perhaps now you can see why the assonance of the Chinese struck me so forcefully.
Finally, here is the original Latin for the hymn, in which I shall note the assonance and rhyme.
Pange, lingua, gloriosi [A]
Corporis mysterium [B],
Sanguinisque pretiosi [A],
quem in mundi pretium [B]
fructus ventris generosi [A]
Rex effudit Gentium [B].
Nobis datus, nobis natus [C]
ex intacta Virgine [D],
et in mundo conversatus [C],
sparso verbi semine [D],
sui moras incolatus [C]
miro clausit ordine [D].
In supremae nocte coenae [D]
recumbens cum fratribus [E]
observata lege plene [D]
cibis in legalibus [E],
cibum turbae duodenae [D]
se dat suis manibus [E].
Verbum caro, panem verum [B]
verbo carnem efficit [F]:
fitque sanguis Christi merum [B],
et si sensus deficit [F],
ad firmandum cor sincerum [B]
sola fides sufficit [F].
Tantum ergo Sacramentum [B]
veneremur cernui [A*]:
et antiquum documentum [B]
novo cedat ritui [A*]:
praestet fides supplementum [B]
sensuum defectui [A*].
Genitori, Genitoque [D*]
laus et jubilatio [G],
salus, honor, virtus quoque [D*]
sit et benedictio [G]:
Procedenti ab utroque [D*]
compar sit laudatio [G].
Arguably, I am being too generous with the Latin by grouping technically distinct sounds under the same phonetic-letter, but, for one thing, Latin is a famously assonant language, so I don't think I'm violating the "phonetic sense" by which "Pange Lingua" was composed, and, second, I was actually being magnanimous in my analysis of the English version by keeping very obliquely assonant phonemes under one heading. Clearly, the Chinese edition strives, and succeeds, to duplicate the assonance of the original Latin; indeed, it seems to have outdone it! I admit this is not a huge shock, considering how homophonic Chinese is, but it was a small breakthrough, or perhaps just a milestone, in my ongoing absorption of Chinese.
Since talk is cheap, I leave you with a fine rendition of the hymn with Latin subtitles (and on a Chinese website, no less!).