Variariations of place of articulation

Dentalization

when /t, d, n, l/ are followed by /ð, θ/.

Inside a word: [ten̪θ] [wɪd̪θ]

At word boundary: [ɔl̪ θru:] [ɪn̪ ðə] [ət̪ ðə]

Labiodentalization

when /m, n/ are followed by /f, v/.

Inside a word: ['kʌɱfət] [ɪɱ'vaɪt]

At word boundary: ['tɪɱ 'vəʊtɪd] [ɪɱ 'fəʊkəs] 

Postalveolar Articulation

when /t, d, n, l/ are followed by /r/

Inside a word: ['bɔ:l̠ru:m] ['kʌn̠t̠ri] ['lɔ:n̠d̠ri]

At word boundary: [bɪ'gɪn̠ 'raʊz] ['sed̠ 'red]

Clear /l/

when /l/ appears before vowel sounds or /j/.

[læmp] - [ˈjeləʊ] - [kɔ:l aʊt]

Dark /l/

when the phoneme precedes consonant sounds, /w/ or pauses.

[wɪsɫ//] - [maɪˈseɫf] - [ɔ:ɫweɪz]