Spanish, Italian, and Portuguese Similarities

SPANISH
Todos los seres humanos nacen libres e iguales en dignidad y derechos y, dotados como están de razón y conciencia, deben comportarse fraternalmente los unos con los otros.

ITALIAN
Tutti gli esseri umani nascono liberi ed eguali in dignità e diritti. Essi sono dotati di ragione e di coscienza e devono agire gli uni verso gli altri in spirito di fratellanza.

PORTUGUESE
Todos os seres humanos nascem livres e iguais em dignidade e em direitos. Dotados de razão e de consciência, devem agir uns para com os outros em espírito de fraternidade.

Notice that Italian and Portuguese agree in syntax and in certain choice of words in:
....devono agire gli uni verso gli altri in spirito di fratellanza.
....devem agir uns para com os outros em espírito de fraternidade.

against:
....deben comportarse fraternalmente los unos con los otros.
in Spanish

But in the first sentence, the three languages are almost the same in syntax and words.

Spanish & Portuguese sintáxis are similar in 89%
Spanish & Italiano in 82%
Spanish & French in 75%

Spanish and Portuguese developed from one Vulgar Latin variety,Italian developed from another.

Spanish and Portuguese, as well as Sardinian and Romanian preserve many archaic Latin words that dissapeared in late Latin and Italian Romance.

Be that as it may - by the provided examples. Spanish and Italian are sonorous tongues than Portuguese will ever be. Besides, at times Spanish / Italian and Portuguese can be manipulated so they can coincide. Suffice it to say, historically Spain had a 200 year-old history in modern-day Italy.

....devono agire gli uni verso gli altri in spirito di fratellanza.
....devem agir uns para com os outros em espírito de fraternidade.
....deben actuar unos con los otros con el espíritu de fraternidad

What's a sonorous tongue? Could you give some examples for us to hear all this sonority?

Sonorous:
1. producing sound: producing or possessing sound
2. resonant: sounding with loud, deep, and clear tones
3. having impressive manner of speaking: speaking, spoken, or expressed in a rich, full, and impressive manner

Italian is definitely resonant, upon sounding with loud, deep, and clear tones. Some Spanish variants do too. The following bits are how Nuoro / Logudorese sound like, the island has been influence by many languages and cultures - preferably Spanish and Italian. One can tell by hearing the provided examples that this NUORO language was influenced by the aforementioned.

Three - click on "NUORO"
Here are some examples of how Italian and Spanish sounds like:
http://www.mondosardegna.net/all-lang/linguasarda/linguasarda.php?LANG=eng&f=numeri/tre&word=Three

November - click on "NUORO"
http://www.mondosardegna.net/all-lang/linguasarda/linguasarda.php?LANG=eng&f=mesi/novembre&word=November

Warm - click on "NUORO"
http://www.mondosardegna.net/all-lang/linguasarda/linguasarda.php?LANG=eng&f=varie/caldo&word=Warmth

September - click on "NUORO"
http://www.mondosardegna.net/all-lang/linguasarda/linguasarda.php?LANG=eng&f=mesi/settembre&word=September

I can't see how Italian sounds with louder, deeper, and clearer tones than any other language.

"resonant: sounding with loud, deep, and clear tones "

yes i agree with you, italian and spanish are definitively sonorous.
except maybe for the deep voice, have you ever heard an spanish or italian speaking?

seem some chickens clucking so highpitched that it is the voice.
in this matter portuguese definitively is distante from these two languages.
deep voice is something that the italians and spanish dont have.

japanese have deep voice.korean.portuguese.french.german.

@ a more original name

Whoever said Italian is sonorous than any other language? Your concluding false premises. I have made an assessment of the three languages, those being: Italian, Spanish and Portuguese.

I said that it is not more sonorous than any other language, and not that it is more sonorous than all other languages.

@ rafjed

Argumentum ad hominem. Portuguese is closer to French phonology, as both have many vowels.

">I said that it is not more sonorous than any other language, and not that it is more sonorous than all other languages.<"

Circular argument.

Syntax means word order in a sentence and definitely not synonymous to lexicon.

Spanish and Italian are closer to each other in phonology than to Portuguese.

Spanish and Portuguese are closer to each other in lexicon than to Italian.

But when it comes to syntax or word order, Italian and Portuguese are closer to each other than to Spanish.

@ La Hostia

We have a few words derived from the French because France was a big influence to us during the 18th and 19th centuries, cultural and socially.

I know french and a bit of Spanish and Italian, but if i had to choose a romance language i would pick Italian because its accent is the easiest for me to capture. Although the history says that Portuguese and Italian took different routes long ago, i think that they're still very similar, in some ways more than with the Spanish and French, phonetically for instance. And i'm not the only one, many English speakers say that too, if they say so i believe it because the only way they differ a romance language from another is by the accent.