Here, we are going to do a little autopsy of the Spanish phonology and understand how it can help us improve our vocabulary effortlessly and more naturally. Words retained this way tend to retain for longer.

Spanish has simplified the Vulgar Latin vocal system to only 5 open vowels (as in Classic Latin) -- a, e, i, o, u -- that are pronounced clearly and without reduction in both stressed and unstressed positions. The vowels, that are short in Classic Latin, diphthongize when stressed in Spanish, except for a:

CL porta door -> Sp. puerta,

CL herba grass -> Sp. hierba.

The long and stressed vowels, e, o are replaced by i, u, and the short and unstressed vowels i, u, by e, o:

CL fêci (I) did -> Sp. hice.

The accent may fall on the ultimate, penultimate or antepenultimate syllable. Its place is recognizable from orthography. As compared with the accent of Classical Latin, it shows a tendency to move towards a syllable containing –r:

CL tenebrae darkness -> Sp. tinieblas.

The Latin consonants p, t, c between vowels are voiced to b, d, g in Spanish:

CL apotheca (th=t) store-room -> Sp. bodega.

The intervocalic -d- disappears (CL cadere to fall -> Sp. Caer), and the intervocalic -g- may disappear or become a glide sound [j] written y (CL legere to read -> Sp. Leer; CL reges kings -> Sp. Reyes), while the intervocalic -b- is preserved, but tends to become aspirated as v (CL habere to have -> Sp. haber).

The initial f- is replaced by a mute h-:

CL facere to do -> Sp. hacer.

The consonant clusters ct, lt are transformed to ch (act to ech):

CL octo eight -> Sp. ocho,
CL multu (m) much, many -> Sp. mucho,
CL lactuca lettuce -> Sp. lechuga.

The clusters cl, fl, pl are palatalized to ll:

CL clamo (I) call -> Sp. llamo,
CL flama flame -> Sp. llama,
CL ploro (I) weep -> Sp. lloro.

The clusters ali, eli, ili, oli, uli are transformed to aj, ej, ij, oj, uj:

CL alium garlic -> Sp. ajo,
CL filius son -> Sp. hijo,
CL mulier woman -> Sp. mujer, etc.

The clusters lr, mr, nr are divided by epenthetic -b- or -d- and become ldr, mbr, ndr, as in:

venir to come + he (I) have -> vendré (I) will come.

The words beginning with s- followed by a consonant (s impure) receive a prothetic e-:

CL stare to stand -> Sp. estar.

With this insight into the fundamental structure of Spanish and its semblance to Latin, the parent language of all Romance languages and a major contributor to the English vocabulary, you will be able to understand the anatomy of Spanish vocabulary better and enhance your vocabulary more naturally. Given that many English words derive from Latin and Latin is a direct predecessor of Spanish, you will, more often than not, discover Spanish words that have not-so-distant cousins in the English language too! Makes learning easier?