Meled hadhod sui chadhod—'orn, dhern. Ú-guina amann.

To love a dwarf is as a dwarf—twisted, stiff, difficult. It lives not long.

The only known example of a linnod is Gilraen's Linnod, and since it is comprised of two lines of seven syllables each, Tolkien linguistics scholars have theorized that perhaps it means 'song of seven'. Like the rendering of Elvish verse into Westron using ann-thenath, it might be an established cultural meter or form of delivering poetry, just as English sonnets or the borrowed form of haiku from Japanese.

Even more literal translation:

Loving [a] dwarf [is] as/like [a] dwarf—twisted, stiff, difficult. (It/he/she) is alive not long.

No one is this effing literal translation:

Meled (v.; gerund [Note: Sindarin often uses the gerund form of a verb where English would use the infinitive. The 'strict' infinitive form would be *meli (v.; infinitive) or *melo (v.; infinitive). Consider also *Melad (v.; gerund) if mela- vs. mel- is the true stem [VT/45:34 lists the Noldorin stem as mel-.].]: "Loving, To love"

Hathod (n.) "Dwarf" [Note: this Sindarin term is derived from the Khuzdûl word Khazâd, the Dwarves' own word for dwarf. It is the politest and only politically correct way to describe or address a Dwarf within Tolkien's legendarium if you are a Sindarin (or other non-Quenya Common Eldarin dialect) speaker. So naturally, it is rarely encountered. Most of the Elves used terms like "the thrawn folk (dornhoth, dernlir, gornhoth)" or "the stunted ones (naugrim)" without ever questioning the inherent racism and years of hatred embedded in those words.]

Sui (conj., adv.) "as, like"

Hathod (n.) mutates to *chadhod as it is the second noun in a 'noun [to be] noun' phrase.

Gorn (adj.) mutates to *'orn because it describes a noun. "Stiff, hard, thrawn". May also translate as "Impetuous, hasty, vigorous." [Note: It is also a word that was used by the Sindarin speakers to refer to the Dwarves as a people. Used in this context—where the speaker at first purposefully refers to the Dwarf by by a Sindarinization of the phonemes for the Dwarves' own term for themselves Khazâd—it is a bitter (and rather racist) pun.]

[Note: a homophone means "valour".]

Dern (adj.) mutates to *dhern because it describes a noun. "Hard, thrawn, tough, difficult." [Note: it is also a word that was used by the Sindarin speakers to refer to the Dwarves as a people. Used in this context—where the speaker at first purposefully refers to the Dwarf by by a Sindarinization of the phonemes for the Dwarves' own term for themselves Khazâd—it is a bitter (and rather racist) pun.]

Û (adv.) changes to *ú- when prefixed to a verb, adjective, adverb, or noun. "not"

Cuina-(v.; stem) conjugates to *cuina (v.; third person singular present tense [Note: translates literally as "he/she/it" without any further specification. One can assume it refers to either the act of loving a dwarf, the Dwarf in question, or both, or all three at once. One might also assume the speaker is being intentionally ambiguous.]), mutates to *guina as it has been prefixed by the adverb ú-. "to be alive"

Amann (adv.) "for a long time"